Strange characters in pihole when looking at outgoing messages from FingerprintDoorbell

[Kalored]

I have a FingerprintDoorbell up and working for quite some time now (1-2years) first using the original, then using the MaskedDeveloper and then the Mickler Version. Thanks to all for contributing to that project.

Since quite a while I have a strange behaviour.
The Mqtt Messages appear fine in my iobroker, but the doorbell sends out every 10-20sec. random messages like " ôü?�ïü?xv­ºðaû?4�º«�" via HTTP.
I could capture that in my pihole.
Any idea what this could be?

I am trying to prevent reflashing the system via computer completely, as there is currently no way downloading the fingerprints and make a backup.

I reflashed the system 1-2 times via OTA in the last days, but no change.