Nomad MegaRandom invalid island spawn

My friend and I had a Nomad game today on MegaRandom where in the middle of the lake there was a stone island, which is impenetrable and 1 villager of him had spawned on the edge of that island. He couldn’t make a dock anywhere nor could he traverse the island, so he was basically stuck on the island until he managed to get the villager out, which would take ages. Added screenshot

Map: MegaRandom
Biome: European Temperate
Seed: 03fb03be