I am working on the KarmaKrew server. its all Vanilla.

What the team found is that the server does not communicates well with clients item wise.
if you swap one item for another in your hands, then it gets bugged. The server seems to remember the first item while client sees the second item.
Also other players still see the first item.

It gets resolved when first item is put away and then you grab a new item.

I would like to know if you have any suggestions of handling this.

There are 4 different servers on that hosting PC, and the other 3 do not have the same issue.

To me it feels like the server has not hotfixed properly on the last inventory fix and clients have. Is there anyway to check that in the server files??

We allready set everything back to basics, a new instance and the problem presists.