Grooming plug slugs still has bugs

Witnessed rancher stuck in critter call animation while plug slug ignored calls for grooming.  This usually happens at least twice within a hundred cycles, but I never catch the initial loop.  If this is due to cycle rollover of the next issue, this may be occurring many more times than what I happen to find.

After leaving and returning, the same rancher began calling slug again and was ignored.  This time slug was drowsy and then went to sleep, with rancher continuing critter call at night.  A different rancher wrangled the smog slug during this time, if that has any relevance. 

EDIT:  I just noticed the sleeping slug is groomed, so this is likely due to wrangling and grooming duties being assigned to two dupes at the same time.