The following situation happened towards the end of our last session(I am the DM): A player cast Mordenkainen's Magnificent Mansion, so they could take a break to heal up their comrades and rest a bit.
Then, that player cast the Mansion again (after a long rest) and placed the portal inside the first mansion. Everyone went through before the first mansion disappeared, and expected to return to the main overworld again after another 24 hours.
But technically, the Mansion only expels creatures, not portals to extradimensional planes, so shouldn't they be thrown out where the first mansion was, an extradimensional space?
I am not gonna do this to them now since this would be the end of the story and not something anyone expected, but still: Under RAW, would my players be back to the extradimensional space where the first mansion was?