I have experienced occasional glitches with pregnancy showing in the regular game, so I don't know that it is necessarily related. I had one or two sims who didn't show the first bump, which sounds like what happened to your sim.
I have also had pregnant sims in maternity gear go to work (happens if they get the bump at the same time they are going to work).
that one happened to me this week. I assumed it was the timing being so close rather than the patch.