When repeatedly verifying opaque signatures on Windows you can get GPGME to crash.
This can be tested with the new --repeat argument of run-verify.
It might be at least one cause of T4111. As such a fix for this is very important for Gpg4win.
Here is a signature that triggers this for me:
I copy the run-verify.exe into my Gpg4win folder and run c:\gpg4win\bin\run-verify.exe --repeat 5000 --cms "the sig file"
Please note that due to the crash fixed in 8f27511862cabac8fa1dd8f883cb78faebc05ef6 you also need to update libgpgme-11.dll in gpg4win to not have it crash immediately.
@werner you can already help if you like. Otherwise I'll try to whittle this down further.