Resetting the kalman filters that estimate the vehicle’s motion/position state makes sense when you re-calibrate your depth sensor, otherwise they might register a significant acceleration that was actually caused by re-setting the depth zero-point. Note that it’s a warning not an error - the calibration was successful, so the EKFs are reset to start fresh with the new calibration values
That’s definitely an unusually large offset and range, and if the pressure or measurement time wasn’t actually significantly different between those readings it would suggest to me that your Bar100 might be damaged/faulty.
Note that the Bar100 has a \pm500 mbar accuracy, so depth calculations based on it can conceivably be off by up to ~5m if it’s not calibrated. Its precision is 3mbar however, so it should be able to measurably detect ~3cm of depth difference in fresh water. When the depth calculation is calibrated to a given pressure (the barometer calibration you ran), the estimated depth from that point should be accurate to within the precision amount (subject to water density differences, which shouldn’t be particularly relevant for measurements at/near the surface).
I’d suggest you try putting the ROV in some water and watching the depth readings. If it’s just an offset issue (e.g. caused by different air pressure from the initial calibration location+time) then the calibration you did should solve that, and the readings should reasonably accurately reflect the depth the sensor is at (you can try pushing it down into the water a bit to see the variation).
If the measured depth is varying from what it should be after you’ve performed an offset calibration then there’s likely something wrong with the sensor, in which case I’d recommend you contact firstname.lastname@example.org, and link them to this thread. They can help make sure if the sensor is damaged, and are the people to talk to about a potential replacement or refund