Yesterday I'm running along trying to get to my group of targets, when BAM DX10 error and I'm kicked out of fullscreen. (Note: this is a FFXIV error - I've been dealing with it forever and updating drivers, etc has only reduced the frequency of the issue).
Log back in and the leve has failed. I didn't even get a chance to kill a single mob.
I know this has been around since beta, and is intended to prevent players from exploiting by disconnecting. Which would be fine, if the game was more stable. Right now it's just causing me to waste a lot of time, lose opportunities to gain levels, and for a casual player it could be even worse. If you only can play one or two days a week, and you end up dc'ing for one reason or another, you're just out of luck.
For now, SE should remove the failure on disconnect until they get the rest of the game working.