As you can probably tell from my profile, I extensively use telescope live.
For the sets I have used, bad data is uncommon but unfortunately at the cusp of being a real problem. This can be negated if you have one of the plans that allows you to download their calibration frames so you can calibrate the lights yourself, however it's no secret that you are likely to run into frames that have the following problems:
It SEEMS to have gotten better; my Fornax A came out really nice but frames still had to be discarded. It was nowhere near as bad as say the M77 dataset which is older.
Additionally, some of their setups have really bad tilt and backfocus issues the last time I used their data. The AUS-1 widefield setup is really bad for this. I THINK the Spain widefield setup was as well but do not quote me on that.
It is also possible they have fixed these issues in the interim, but I am not about to use my credits to find out.
I have a hunch that they were not prepared to deal with the smaller pixels of CMOS cameras when they made the switch.
That being said, I have never contacted support about any of this, so I don't want to unduly slander them given that I have never actually asked them to check into any of this stuff. It's fully possible most of these issues have been fixed in the newer datasets.