Can't see one particular player in players tab

I have encountered an error occuring only towards one player which connects through Geyser. Although other players on Geyser as well as normal Java players are showing up normally, this particular has his .dat file there but isn't showing up in the interface. We had already another server on aternos and there was the same issue.

https://preview.redd.it/snpb54kz2gng1.png?width=1129&format=png&auto=webp&s=dae277469ad73fd00130f04194498ef7789b7c9b

https://preview.redd.it/i5hj8tyz2gng1.png?width=461&format=png&auto=webp&s=489d23c05cc14b240d44259d5b09474a260ccd6b