Hi there -- I'm sorry if this is covered elsewhere; I did an extensive search but came up blank. I'm a long time OW member, but usually purchase thru AA, where I hold the bulk of my mileage. .

30 days ago I purchased a flight on BA with return travel MRS-LHR-SEA-PDX on 27 May 2019. 2 of 3 segments are on BA metal (#0367; #049 ) with SEA-PDX on AS metal and ticketed as BA #2839 .
(It's a R/T, but there are no issues with the outbound PDX-DFW-CDG - all on AA metal.)

BA texted advising SEA-PDX #2839 was cancelled, yet today I see (on BA's site, the OTAs and EF) it's still available for purchase.
I called BA who explained the "web site had not caught up..." and offered to re-route MRS-LHR-SFO-PDX, (#3 leg on AS metal) but given the increase in fare (~$250), I declined.
No other SEA-PDX flights are available, they say.

AS flight schedules aside, my sense is we have an MCT issue: #049 arrives 17:15 and #2839 departs 19:00, leaving 1:45 to connect to an AS gate.
I'm usually mindful of this, but I have GE and didn't see an issue here, even with re-checking my bag. ????

If so, there are a number of AS flights SEA-PDX for about $88, so it seems more cost effective to purchase a separate (later) flight on AS.
Great, but this raises concerns as to how BA will want to 'fix' the original ticket... I don't want them to tell me they must now "reissue (at the current fare)...." Given it's the same city pair, IMHO it would be an exchange at best.
How is BA likely to respond if I suggest they simply remove the SEA-PDX leg from the original itinerary? And... given this flight is next May, how long should I wait?

Thanks so much for your help.