Despite what has been said previously in various tickets (e.g. T171360: "Resolved for 1.22 update" and T169697: "Resolved for 1.20" etc.), there are still problems when trying to arm plastic explosives :(
Today on the EXP 1.22 patch launch day I immediately went looking for some plastic explosives and detonators to see if it's finally fixed, unfortunately this happened on my first try:
As you can see the plastic explosive didn't arm and I lost the remote detonation unit in the process (which was never the case before). All I'm left with is the plastic explosive itself and a remote detonator that became useless because it isn't attached to anything.