sorry i haven't even read the first post.
anyway it's not bugged as much as i know, but it's 99% that you've made a mistake somewhere and it's hardly reachable / understandable where. that happens because we have events based engine which is sometimes hard to decrypt what happens.
anyway this could also happen if timers use threading. using many threads (each minion owning a thread) could cause issues if undelayin' performance is bad or optimization is not perfect. i've had my share of playin' with threading in c# where lots of stuff is perfectly declared what you can do and can't do, and trust me, it becomes a pain in the ass over some time to sync events.
using wait probably pauses that single picked instance and blocks that thread until time runs out and continues the thread then. using timer probably creates a new thread for counting down the time and stuff gets easily bugged. if wait works for you, then use it. if you really really really want to use timer, at least supply the part of code where we could see what happens and direct you into fixing stuff (or waste another day finding why it happens).
(it's the same as when i optimized 6 events shooting into 1 event (works like a charm ) )
also why would you use "timer.time - 1 sec" thing?
i'm a show you a part of my code how i set how often my enemies shoot. (Timers)
oh yeah, difficulty - easy, medium and hard are described by 1,2,3.
so you get 1.2*(8/3*1) = ~ 3.2 sec for easy, ~2 sec for medium and 1.2 sec for hard.
oh yeah, i think i could have done this differently too - set a timer that is called every those sec, and call the upper function (swap places of on timer ) - but i think that would be slower. why? timer would fire it's part of code every time. and this way i check if fireing is disabled, if it is don't fire timer. else fire it.