Most of the Sunwing issues have been caused by their pilots essentially working to rule as a result of the proposed acquisition by Westjet. This includes a refusal to go into discretion and refusing to work if "rest" is disturbed, for example by a phone call delaying report to avoid going into discretion. Longer flights like ABZ-DLM become particularly vulnerable.
Unfortunately it's British customers just trying to go on holiday that end up caught up in an industrial dispute that's happening on the other side of the Atlantic.