Originally Posted by
lotemblizej
One possibility here is that the system mistakenly prioritizes ANYONE who requests both upgrades (Y to PE and PE to C) over those who request only an upgrade from Y to C. Thus, a silver could leap over a GS or 1K on the list into C. Most of the problems reported seem to relate to clearing into C, not PE. Just speculation, but the cause appears to be a major glitch in the new system that, as pointed out above, may be hard to diagnose and fix.
I can see how this might erroneously happen. If UA's computers upgrade someone from Y to C, they may then count that person as a C passenger waitlisting for F. That passenger may then be seen by UA's computers as having priority over a Y customer only waitlisting for F. Certainly something that needs to be fixed if this is what's happening.