Yes it was very common some months ago but is mostly solved now. Back then we had 4-5 players trying to get into a dungeon. none managed so some left other we had to kick and try again last got in while on last boss, awesome tank told us to not damage boss so the poor guy could at least get him.It usually implies there already are 4 people in the instance. Happens a lot when #4 drops, group queues for new #4, gets him, but the old #4, while no longer in group, is still in the instance(or the game still THINKS he is there at least) so the game cannot port you there. This should go away after a minute or two and then you'll be good to go^^
Assuming you mean you dropped group on your own after being unable to port to it. If it auto kicked you well that's weird. "Jump failed, instance is full" is its standard message for the situation I described above.