it seems that PM 4.6.6 is also forgetting the {seqn} variable after shut down...
I'm getting the same issue but it's not just on a shutdown.
I've just shot my second weekend worth of events with 4.6.6 and I've had the ingress {seqn} issue on both of them. The strange thing is... sometimes it works and sometimes it doesn't.
Sometimes I'll put in a card and notice that the ingress screen has popped up and the sequence number has increased to one greater than the last image number (the correct behavious). Sometimes the screen will pop and the sequence will be the same as the starting number of the previous ingress (this causes a duplicate numbering and the addition of lots of 'A' versions). I thought it was related to using alternating flash cards, but I've seen it with just one card now.
At the last game I resorted to setting the seqn numbers by hand on each ingress. It worked fine for me on 4.6.5.
I've thought about getting some screen shots, but I'm always on deadline.
Dean