The first one is due to how the Helmsmanship elite perk works - right now it allows you to retain the 0-flux boost while venting or overloaded, since you're technically not building up flux at that point. This is changed for the next build.
Second one, I'm not sure why they wouldn't retain the ability to strafe. Neither of those status effects directly affects mobility.
Third, I can't say - haven't seen any similar issues. The overload duration is dependent on the amount of "extra" damage that hit the shield, though, so if they were overloaded by a small shield hit and had elite Reliability Engineering (which reduces the duration by 30%) I can see it being shorter. But not quite 2 seconds; the shortest base duration - for a frigate - is 4 seconds.