we experienced a very unusual event recently. when investigating a Micromotion hard-wired 4-20 ma flow that was off-scale high, along wiith the Micoromotion rep on site, we found via AMS Device Mgr that the HART variable was fine but the hard-wired analog was saturated high. The URV was originally set to 1250 MSCFH but when we looked at it, it had changed to different number: 120. I entered 1250 in the URV and sent it to the device, the flow changed slightly. I checked the URV and it had reverted to 158. after attempting the change several times, it always came back to 158. we tried putting 10000 as the URV and the flow came closer with the URV showing slightly higher than the HART parameter indicated. eventually, via trial and error, entering 9840 gave us 1250 as the URV after the process completed. any idea what is going on? is it a DD file issue? we use the AMS lite version12 for wireless but have never seen this issue. not sure if using a 475 would have made a difference, but it was likely that is how the instrument was originally set up prior to the THUM installation. Thanks for any insight you can provide. the unit is in hydrogen gas service.