Every time a DLL is loaded, a new temp file is created and never removed. I now have several dozen folders called MumbleLink7060520309212793916native. A similar problem occured on another project I worked on: andrew-hoffman/halfnes/issues/37

This has to do with how JNA unpacks the native libraries. I would assume it doesn't use the deleteOnExit or this is unreliable (maybe the normal Minecraft shutdown is not considered a normal termination of the virtual machine.

Is this issue still existent on normal MC exits?

Sorry, I don't have information on this anymore and I primarily use Fabric now. I did some work on extracting temp files here to use here that might help if it comes up in the future again though.