Game Mechanics: Fear instantly breaks

[DoucLangur]

My first suspicion was a different aspect: Could it be that in those circumstances, the Fear spell did never actually break, but was instead overwritten by your next cast and this erroneously causes the worn off message (as you get it when someone else overwrites your root/snare)? And that a timing bug on serverside causes the goblin to not "notice" it is feared, and behave like an unfeared mob?

The other explanation given sounds more likely, but I thought I would share my thought anyways.

[finalgrunt]

It is not overwritten, as it happens even on the very first cast of fear. And the mob is never feared for subsequent casts. Always breaks instantly.