Possible portal exploit?

Me and my friend just finished a map and saw that we still had 5 portals left. Somehow we managed to both enter the same portal. https://cdn.discordapp.com/attachments/917742187679207424/1145722853136814160/image.png Im not sure how we managed this or how to replicate it, not that we want to replicate it. Hopefully this helps highlight a potential exploit.