Blue resets inconsistently [gameplay]

So, I've been playing a lot of jungle lately, and i've noticed that the blue camp specifically is not reseting at five, but very inconsistently. it sometimes resets at two or three walk backs/attacks. i have literally been in range of it to attack me and it completely ignored me after only turning or going back and forth twice. this is specifically something that has been happening with vayne jungle, but also with fiora. the problem with the inconsistency of this is exactly that, it's not consistent and i haven't been able to reproduce it every time. i haven't noticed this problem with any other camp, only the blue buff. i'm wondering if it isn't something to do with champions that can move into range quickly and the camp ignoring that and it resets as you become untargetable for a brief time. given that you can instantly attack out of vayne's q or fiora's q/double q i'm not sure why it wouldn't immediately aggro again, but it has been doing that. but it has also reset when i was just standing there face tanking it as well. suffice to say this is somewhat frustrating, even if it is off meta junglers that it is hurting specifically since the ones that are played in the meta don't have to worry quite as much about microing their damage/health on the first clear.