Problems with live-rec mode in M: S (trigs disappear)

Hello, I recently noticed one nuance in the operation of my device. Sometimes, when I do a sequence, an error occurs in the device. For example: I work with a track in which the sequence steps are already recorded, if I turn on the LIVE-REC mode and start to beat new beats, the sequence steps begin to disappear. sometimes new steps disappear, sometimes active ones disappear, what’s wrong with my device? Thanks