I have this issue as well and it can be quite annoying...
It happens to me on official, community, stable and experimental servers. Usually I have to connect 2-3 times to a server before it will let me join.
I think this problem started around the time that version 1.22 EXP got released. I don't know if it happend to me when I played 1.21.
@Geez Are you around somewhere? :)

I've had this issue as well a few times. I think it's not just because of the steps or stairs but when there's a slight height difference between the player and the infected corpse.
For me this problem only occurs in 1.22 EXP, not in 1.21 stable

Just to let you know I found these plastic explosives and remote detonation units in this 1.22 patch, I've had nothing left from the previous patch. I usually suicide when a new EXP patch comes out and this time was no difference.

It's not fixed (yet): https://feedback.bistudio.com/T174303

That's very strange, to say the least. I've tested it twice on the same official experimental server on different occasions and the results were the same. My video is also recorded on this official server so how would you explain this then?
Did you guys perform these tests on a freshly wiped server? Because my suspicion is that problems related to arming explosives could have something to do with the up time of the server. In the past I almost never had problems arming explosives when the server was just wiped recently. Based on my experience these kind of problems mostly start to occur when the servers are up for a longer period of time, usually a few weeks after being wiped. To me it seems that the longer the servers are up, the harder it becomes to arm the explosives.

I like this idea. This would make raiding bases a whole lot easier and faster by brute forcing the combination :D
I don't think the devs would like this too much though...

I can confirm this. It also happened to me as well one time when I tried to combine a stack of 20 pristine 308 rounds with a stack of 11 damaged or badly damaged rounds. The stack of 20 pristine rounds disappeared after the combining action.
I don't think it happens very often.

I've already made a ticket (with video) about this but unfortunately it got closed by @Geez for being a duplicate? (Which it's not if you read it carefully) https://feedback.bistudio.com/T172487
Can't really blame him, it was almost weekend at the time... :-)

It happens to me as well, not always but sometimes (even on the latest experimental update).
@Geez: When it happens, I keep trying to arm the explosive multiple times (from different positions), usually I can arm the explosive this way but it may take up to 50 tries.

The devs already know this, they even mentioned it in the patchnotes.

In case it helps: Till about a week or so ago, I never saw them on a wreck before, they were always available only through sheds etc. Now they seem to be available through both sources (wrecks + sheds).

In T170418#2413416, @Geez wrote:

Hello Timmay4356.
We could not reproduce this on our end.
Is it possible that there was some sort of desynchronisation happening on the server at the moment?
Regards,
Geez

Whilst roaming around on the Chernarus map I've came across another few...

Nvm, I just found out it's already reported: https://feedback.bistudio.com/T168326

In T170089#2403705, @Geez wrote:

Hello Jordi435.
We have tested this internally and the grenades do spawn.
Regards,
Geez

Well, if that's the case (which I doubt with vanilla settings) then these wheels spawn way too frequent. I can find these wheels in almost every town I go (on Chernarus).

I can confirm this bug. As of today, it's still present and very annoying to say the least... (same with the other unfixed bugs related to plastic explosives)

This bug is still not fixed properly. Sometimes it works like it should and sometimes it does not. In 1.19 (latest EXP patch as for this moment) I've managed to ARM it the second try on two different occasions.

And again: Same server, a different base but again a gate in a doorway:

So, I've found another base on the same server in a different building and it happened again:

No, it's a vanilla community server (Dusk) that doesn't require you to load any mods. It only has a few small tweaks like a little bit more stamina and some old (pre 0.60) SKS/Mosin skins but those should already be in the original Dayz files.
Maybe this bug has something to do with the gate slightly clipping through the metal door behind it which you can't see. My guess is that the game thinks the gate is behind the metal door but visually it's (obviously) not.

I've made a video about it:

In T166066#2333169, @sileed wrote:

we also had players report that the same shed always spawns multiple plastic explosives. Wiped our test server and sure enough that same shed is still spawning multiple explosives. We do not have loot turned up (in fact some of it is turned way down) but it seems the world doesn't have enough space to place these industrial tagged items so it constantly chooses the same places.

I don't find THAT many, I think it's fine like it is at the moment.
Also remember that we need to be able to find enough of these explosives in order to be able to raid/destroy bases as grenade damage to doors/walls has been nerved by A LOT. Bases cause huge server performances issues and therefor the amount of bases needs to be reduced to a minimum.

I've had the same thing although I cannot seem to reproduce this bug every time. Sometimes the arming process works like it should and other times it doesn't (same location).
This morning I wasn't able to arm it the first time and also couldn't pick it up afterwards. When I tried it a second time, I was able to arm it but in most cases I can try as many times as I want but it won't do it and I lose my plastic explosive :(
I'm not sure if I used the same 'Remote Detonation Unit' when i succeeded the second time, maybe using another one 'fixed' it that time?

I've never seen anything like that... In fact yesterday I experienced the opposite.
I was playing on a (stable) vanilla server and even though I was almost right under de impact zone of the gas attack (so I exactly knew where to look afterwards), I couldn't find ANY PO-X Vial when the gas was gone.

This ain't no minor bug and should be fixed before the stable build launches.

This bug really should be fixed before the stable build launches (june 14th). I lost several 40mm grenades because there's no way you can stack them so they will disappear when you unload. @Geez Do we have your attention? :)

I've had the same issue but only when moving grenades I had obtained in the first EXP patch, grenades obtained in the latest patch seemed fine.

I can confirm this problem (bug?) exists but I believe it was already present since 1.17, maybe a little worse?
Makes hiding mines by placing clothes over it a real pain now :)

This bug still exists in EXP 1.16...

Update:

• It seems like allot of windows (if not all) in this building have this problem, also the ones in the tower.
• There seems to be no problem when you shoot from the outside into the building, so it's basically some kind of one-way mirror...

This problem/bug is still in EXP version 1.16. Also It doesn't seem to matter what gun/rifle you use.