I didn't have this problem pre 3/3 on the old UA site:

My SIN-NRT-SFO-YYZ flights are showing up in the order SIN-NRT, SFO-YYZ, NRT-SFO now when I look at my reservation (or look at seat assignments), presumably due to the fact that in local time zones, SFO-YYZ (16:02 - 23:58) begins before NRT-SFO (17:25 -10:35), but in GMT they would be in the correct physical order. All the same calendar day of course.
Nice programming there...

On an unrelated note, in the same itinerary, my 2 waitlisted upgrade segments appear at the end of the list of flights (i.e. those segments appear once as economy, and then again as business waitlisted), which is fine and good, except that now the line that says "... you will earn up to XXX award miles" includes the waitlisted segments (i.e. is double-counting those segments and therefore misleadlingly high)!