Alaska keeps saying the chaos isn't related to organized pilot activities linked to contract negotiations, but I am highly skeptical.
This is now the second wave of cancellations and schedule disruption. The first wave started on the same day that off-duty pilots were holding a demonstration outside Alaska HQ. Now this second starts on the same day that the pilots union is holding a strike authorization vote.
What I think is going on is that Alaska has been relying on pilots to accept added overtime assignments. Their operating margin with pilots is currently so thin, that is easy for the pilots to throw the schedule out of whack if a relatively small number simply cut back on (or entirely stop) accepting these overtime assignments.
Publicly, Alaska won't attribute it to pilot action, because the pilots are entirely within rights to turn down those requests, and if Alaska were to try to blame it on pilot action it would poison the continuing contract negotiations.
IMHO, the pilots know they can inflict pain whenever they want to, and are being very effective in applying pressure to Alaska to come to an agreement. They are making the point to Alaska that their cooperation in accepting additional work assignments is vital for Alaska to maintain keel. And the way to enure that cooperation is to make some concessions in the labor contract.
Don't be surprised if relatively soon Alaska and the pilots union announce agreement on a new contract.