Conshelf II supported 6 divers for 30 days at 10M in 1963. All the documents and films that I can remember indicate they all came straight to the surface with no DCS.
I was watching the documentary recently, and I remembered at the beginning Cousteau visits the crew in the main habitat, then has to return to the Calypso, but mentions in the narration that he will have to decompress for an hour at 10' under the hull of the ship.
I can't recall other mentions of having decompression obligations, but there seems to have been a distinction between those in the habitat and those servicing them - bringing food and mail down in pressure pots, the barber from the ship coming down to cut hair, etc. - that seems to suggest those in the habitat couldn't necessarily surface at will.