All I have to do for the problem to occur with these files is to include a delay for the feedback message to come up. I tried 500, 1000 and 2000ms. The feedback message comes up and goes away without pressing any keys (like it's supposed to, I think), but the rest of the row is skipped.

So, if I don't press a key within the 1500ms specified in the style file for 'stim 1b', the feedback message comes up and then goes away, but I never see the '750 ms pause' or 'end of trial'. Those stimuli are skipped. The next thing that comes up is the start of the next row.