Don't Be Locked Out of the Dungeon

So the dungeons have a limited amount of runs per day. That's fine.
They also have a cooldown (wait time) ... that's fine as well I guess.
But now apparently, upon leaving a dungeon you also get locked out? Even if you haven't finished it? And even if the cooldown has 30mins left on the timer? .-.

This has happened multiple times.
1. Saw Coiste Bodhar for the first time since the start of the event (well into it) so I left the dungeon to rush and buy a mark ... came back and couldn't get back in. Wasted my candies.
2. Had to leave once to empty bags, another time to restock pots. Came back and it was locked.
3. Game crashed and I had to force close and re-open. Locked out.

I hadn't hit 'reset' any of these times as I'd obviously intended on returning to the point I'd left. I run them solo so its not always easy.

Edited for Suggestion:
I suggest allowing players to re-enter dungeons after they have left until the end of the cooldown, or even up until 5minutes before the end of the cooldown if it's really that important.
Unless someone can perhaps shed some light on why this is at all necessary, I really don't believe it is.