wtf. Why temple closes after you leave?..

I did tree runs back to back. Two times I could leave, go to hideout and whatnot, drop or pick up shit and get back. And I thought that this is the intended way to use temple. But now I find portal closed even though it took me less than a minute to return.
What is going in with this game?..

Same, only I didn't even got to hideout, just went to dump loot in the stash, BAM, it's closed. Two new rooms were looted beforehand, — I used some surgeon on myself, and grabbed crystallized corruption from other, maybe one of those was the trigger. Would've been nice to have some sort of a head's up. Room were I got crystallized corruption mentioned that it will destabilize after I finish it in the description, but not it didn't say the whole temple will force-close itself, I assumed it will disappear when I close the temple, as usual...