Yes, I'm sure that e-cas did not deliberately mean to call the principal applicant "null." Normally when you log in there (or when you get AOR, although I'm not sure if Damascus sends those out because I am not going through that VO), it will say "We received *name of the principal applicant*'s application for permanent residence on x/xx/xxxx" (obvi with the name of the person who's applying for PR in place of the ** and with an actual date in place of the x's). So if yours omitted that, my presumption is that it is due to a bug. E-cas is not very reliable, by the way. It has been known to remove info at times too. GCMS notes are the most reliable thing you can get about your case.