This is particularly weird because I don't have it set to a fixed timer to reset aggro, it simply resets if it hasn't been attacked in over 15 seconds.
I'll have to add some logging, I've also asked around to see if anyone else has experienced this
I unfortunately wont have a quick fix for this since its so bizarre, so if you would like to request a refund and try out another crab script I am in full support of that and you can post this reply in your refund application here