Ok, could reproduce it but it is hard and you need to be really quick. What you get is:
15:05:44.969: N723 G90
15:05:45.103: N724 G1 Z1 F500
15:05:45.269: N725 G91
15:05:45.272: N726 G1 Z1 F500 ; *** THIS IS THE PROBLEM
15:05:45.272: N727 G90
15:05:45.428: N728 G91
15:05:45.443: N729 G1 Z1 F500
15:05:45.443: N730 G90
it is not omitting one but both as you need to hit the time where analyser has just switched to relative mode. So the error in this case comes from the host using stale analyser data since the commands have not been processed completely.
Will think about a solution.
