The ex raid gym indicator is now live and as a result changes have been observed to eligibility.
It used to be that all gyms in the dark green area on the map were eligible, but this resulted in people taking a gamble when there were 2 or 3 such gyms in a level 14 s2 cell, or left them wondering why they didn’t get a pass.
However this has now changed, with latest update, only 1 gym in a level 14 s2 cell can be labelled “ex raid gym”.
While this helps clear things up for people who have multiple gyms nearby that meet the prior requirements, I can see this potentially causing more problems for people who have 2 gyms nearby that meet the old requirements, but both are in same cell and no other eligible gyms for miles around. Such people will now only be able to have an ex-raid occur once a fortnight, whereas before they were able to alternate between the gyms to get one weekly.
It would be interesting to see if once passes go out, the ex raid gym label is swapped to another gym in the same cell if others meet the requirements or whether it sticks to the gym that the ex-raid has been triggered on.