Yeah, creeps get randomly stuck all the time in several locations depending on where they land. On the base it's pretty common if the enemy cuts them early from the rail.
If the safe to leave message didn't appear, that's because they didn't abandon, but they have disconnected. After 5 minutes of disconnection from a player the game automatically becomes safe to leave.
That being said, I know that there's an automatic penalty system in place for leavers, and it...
If you want to browse the community builds during a match, the community builds coordinator might not available, causing an indefinite "Loading Builds" popup until it times out.
The game still keeps running in the background and it's not possible to close the shop during this state, so you're...