Thank you for reporting.
I’m using PlayerOne Poseidon-C, Uranus-C, Neptune-C II and Sedna-M with KStars/Ekos on Raspberry Pi4/4GB.
KStars/Ekos v3.6.7 is working well on Ubuntu Mate 64bit.
Could you please post precise report to GitHub/issues?
https://github.com/indilib/indi-3rdparty/issues
This issue had already fixed by updating manufacturer’s SDK.
Debugging process was written below.
https://github.com/indilib/indi-3rdparty/issues/684