Don’t forget the reason why kirito can’t remember back then is because his ‘job’ made it that way. When kirito dived during the job, he’d enter Without his overworld memories. Likewise, when he exited, his underworld memories were blocked/removed, so he left with no knowledge of what he did in the underworld.
Since he entered the underworld here ‘abnormally’, he neither had his overworld memories blocked or underworld memories restored.