Yes, I think I have seen that as well. I was just never able to actually confirm that someone had lost a turn but it had certainly seemed that way once or twice. I'll have to start watching for that one a bit more carefully too now that I know its not just a figment of my imagination...
I have seen that point defence problem before in this Version and earlier ones too. Also there is a chance that if the missles are fired close to your ship (within the range of the point defence) and if you don't move they will hit you reguardless of how many point defence you have. It seems point defence triggers off your movement and the missles coming into its range if neither of these two things happens sometimes the point defence dosen't fire. Sometimes also it looks like the computer gets an extra firing of point defence but it may be because missles sometimes come in waves and it is firing during the missle movement phase and then again in its movement phase.
It was noticed by the testers... its been rather hard to pin down an example of it happening though. It doesnt reproduce very often and when it does its always a suprise... Send the save game to Mm if you saved it before the tactical fights - especially it if has reproduced in several battles in a row.