I have a TBS 6205 that seems to be running happily under Linux (Opensuse 15.0) with the open source driver. I use it with TVHeadend.
When I look at Status / Stream in the TVHeadend web UI, I see quite different error rates for the four tuners (see attached image). The error rate for tuner #2 is much worse than for the other tuners, so I don't think this is a question of poor signal but rather it is some feature/artefact of the card itself.
I don't know whether this is something to be concerned about or not. I have no idea what a normal or acceptable error rate is. I haven't found any stated specification of the card's error rates. I don't know if there are any ways to get more information. Can anybody advise whether this is normal?