It’s stated in our Bar30 and Bar02 product pages (and accompanying sensor datasheets) that
The gel-filled sensor must be completely dried once per day or the pressure and temperature readings will drift.
It’s an unfortunate property/requirement of the gel coating on the sensor element - there’s some extra info in this comment.
If you’ve been operating in continually wet environments then I’d expect that’s your issue, but if you have been completely drying the sensor on a daily basis then this could indeed indicate a faulty sensor, in which case I’d suggest you contact support@bluerobotics.com to discuss a potential refund or replacement 