I saw this anime being mentioned somewhere and it struck me, that the title actually kind of lies about the synopsis. It was not that the guy was summoned tot he same "other world" twice, but that he was born in this "other world", then isekaid to "modern world", and then got isekaid again, but now back to his own "other world". He was reincarnated twice, since the 2nd time seemed to be a summoning.
