I connected my ASI071MC Pro using the ZWO native driver and set up a sequence. I changed the Gain and Offset in the event settings for Event 1 to 180 and 60 respectively and clicked OK. Before running the sequence, I revisited the event settings for Event 1, and both gain and offset showed as 180. I changed the offset back to 60 and clicked OK, then revisited the event settings again. The offset again showed as 180.
I ran the sequence (a single bias frame for testing purposes). The actual gain and offset used for the single image were 180 and 60 respectively. I verified that the median value of the acquired image was about 60.
I tried this a few more times with different gain and offset values, and the results were always the same. The sequence correctly uses the gain and offset entered into the event settings, but the event settings panel reports the gain correctly, and always reports the offset incorrectly to be the same as the gain.