As I understand it, ETOPS flights require a mechanics check every 24 or 48 hours or so (by the clock, not flight time).

WJ seems to be running non-ETOPS routes now to Europe (over Greenland) instead of more direct routes.

Today and yesterday's WS34 YYZ-DUB look like this:



Meanwhile Thursday and before's ~12 flights all look like this:

Only adds ~100-200 miles. Doesn't appear to be due to weather as AC800 is taking the direct route.

TATL flights out of Halifax, such as WJA24, are a more extreme example of this, here adding 700miles (24%) to flight distance vs direct (especially since they only have "left" as the option to go around weather):


However, the return flights are taking ETOPS routes, so I guess they're getting checks done in europe.