Thanks aheinecke and dkg.
I havent been able to replicate the fault using the command line (using the exact same command and options that our program is calling)
however our R&D dept have,
The next time it fails and we can replicate it we will try the --homedir fix and see if thats it.
Its the same user in the program and command prompt so we dont think its a certificate issue.

when you double click a key and then click "Export" you get a copy & paste version of the key.

Thanks for the report. It is always good to have such issues documented.

This pretty much matches my test setup. As the crash is in GPGME it is out of Kleopatra's hand. So I'll try to write a test that repeats such a signing for lots of times. I think this is probably some random race condition.

I think that even if the reason is corrupted keys it would be good to handle this better, either in Kleopatra or in GnuPG. e.g. Kleopatra could detect if a keylisting takes too long and offer to do some cleanup programatically.

I don't think I can reproduce it, at least it didn't happen anymore after restarting and continuing the imports. AFAIR it happened after importing the "Master Key", during trying to import the "Release Key" from https://www.chiark.greenend.org.uk/~sgtatham/putty/keys.html
Ah and maybe one more hint: I have several keypairs, so the dialog for choosing the keypair to be used appears in the next step.

I'm also not sure how to classify this issue. I'm giving it low priority for now as we do not have the info to determine if this is a program error.

I think we had that issue in the past and solved it. It probably broke again. There is an external library we use for this dialog and that might have regressed in the latest update.