There are being many reports of followers losing they SexLab Journal Stats. All those cases are being tracked down to Actors on Light Plugin's.
For the little I see most or all the Stats gets reset. This can be explained by some issue with the HasStats native function that on the scripts is used to seed most of the Stats values if return False.
Seems to me that happens when the ESL plugins change position on the plugin's load list and it's Index change. I can't check the native function and the scripts seems fine so wait to see if is really that native function or there are more native functions without ESL support.