NK3C webauthn on gitlab says key already registered

I have 2 nitrokey 3C NFC.
I set with pivy-tool a pin for my first nitrokey. (can not reset this pin already… but that’s another issue).
And i have registered the second as second factor on gitlab.com.
Trying to register the first also as 2FA-Key gitlab says, that this key is already registered with this site.

No… the other one is registered…

How can this happen?

I am also having troubles registering my NK3C with GitLab.
Registering fails with the red LED being constantly on after entering the PIN.

Now the Nitrokey is somehow broken, because whenever I try to use the Nitrokey now, the red LED is on when I am prompted to touch the key. Testing with Nitropy also fails.

NK3 Status outputs:
Critical error: An unhandled exception occurred Exception encountered: CtapError('CTAP error: 0x06 - CHANNEL_BUSY') Warning: no backend was found to use for communication. Please refer to documentation how to install additional libraries.

Model: NK3C NFC
Firmware: v1.6.0-test.20231218

Unplugging does not help. Neither reboot via Nitropy.

I also tried to re-install the firmware. That does also not fix the problem.
When I try to list the FIDO2 credentials and eventually remove a faulty entry, it also bricks with the red LED when asked to touch the key.

nitropy fido2 list-credentials

After some research on GitHub, could it be related to this known bug?
Crash on full IFS #309

Just updated to v1.7.0 and the problem seems to be fixed.