parlay leg graded late

So I had a 5-leg parlay this weekend, and every leg but one settled before the end of the night. The last one hung for almost 12 hours after the game was over. No weather, no injuries, nothing out of the ordinary on that event, at least as far as I could see. Ended up with the payout eventually, but the waiting threw off my usual hedging plan since I didn't know if the thing was going to get voided or not.

Is this just one of those things with grading delays, or are certain markets more notorious for this kind of thing? Does anyone here have ways of spotting what’s going to get dragged out ahead of time, or is it just luck of the draw? Just curious how others handle it, because I really don’t love that feeling of being in the dark with a decent chunk tied up.