Nothing yet.
Please also make sure that the signal quality is decent.
BTW the error from previously was not caused by the TV card whatsoever, it was caused by another device in your system but could cause also troubles for your TV card since the timings for those must be perfect.
I really don't know what you could try, I just saw that you are using a Gigabyte board which are not the best in terms for BIOS support and have many bugs in them, at least that's my experience with them.
Back then (Sandy Bridge) I've also had a Gigabyte board where I had stutters and issues like you've described after I switched to a ASUS board everything was running smoothly again <- I used DigitalDevices cards in that case.
I can only recommend that you post an issue here with the exact description and with the syslog.txt, lscpci.txt, lscpu.txt and motherboard.txt from your Diagnostics.
You can also try to move the card to a different PCIe slot and see if that makes a difference.
Of course also make sure that you are on the latest BIOS version.
Before that you could also try to enable/disable various settings from the PCIe sub menu in your BIOS and see if that makes a difference.
Maybe someone over on GitHub knows how to solve that.