Same problem for me
Book on CO:
tpa-iah CO UDU cleared
iah-sfo CO UDU cleared
sfo-koa UA UDU cleared
koa-lax UA UDU cleared
lax-iah CO (B fare)
iah-tpa CO (B fare) UDU cleared
No problems on way out. On return, CO canceled their two segments. UA didn't see anything canceled. CO didn't know why but rebooked me in B fare.
B fare cleared for iah-tpa 4 days out via elite Y/B upgrade. 48 hours out UA udu cleared for koa-lax. There was one F seat available for lax-iah and I asked to be upgraded. Said it wasn't NF but i was first on WL. F0 next day. 24 hours out could not check in and called, she said im 17th on UDU list have no chance and didn't check me in. At gate in LAX, I was not on list still so I asked gate agent and he checked me in and told me I was 2nd on list.
Very strange, and I guess I dropped the ball by not forcing the point of checking me in, but 5/6 udu for a 1P is good enough for me.
As an OT note, I only received 100% eqm/rdm from UA for my account. I feel since these flights (lax-iah + iah-tpa) were flown as B fares (even though orig booked as M/W) I deserve the B fare mile bonus. UA claims their system sees M/W still, while CO shows B since they had to rebook my tickets after randomly canceling them. Thoughts?