Originally Posted by SuloL

Here's my two cents. With my borderline-obsessive monitoring of EF, I've noticed this many times before, especially on the week of departure. FWIW, these have all been short-haul routes with high frequencies, and whenever this happens, the flights are mostly overbooked (resulting in op-ups from Y).

I've taken it to be the CX revenue management algorithms in play. They'll try to sell whatever they can - and have capacity for - a few days prior to departure (Y may be already overbooked, but W/J may have seats to op-up people to). This just happened to me over the weekend. I booked a flight on Friday (at the time S9) and when I checked EF on Sunday, it was Y0. And I think I must have witnessed this at least a dozen times before.

Of course, with OP's case, the underlying reasons might be different (CI disruptions etc.). However, I see this as something that CX does regularly (at least on some routes) rather than a special situation.