Bedrock players cannot see their own skins
On my Paper MC 1.21.8 server, Java players can see Bedrock skins. However, Bedrock players are not able to see their own skins. Instead, Bedrock players see one of the default, generic skins instead.
I am using Floodgate build 118 and Geyser build 904.
Java player looking at Bedrock player:
Bedrock player looking at themself:
Note that this issue does not occur if I remove Floodgate and only use Geyser. It only occurs with Floodgate.
I expect this to be a Geyser issue since Geyser is responsible for setting the skin according to what Floodgate provides. Since other people can see the correct skin I think it's a mistake in Geyser, but I'll keep it here until this can be confirmed.
I can confirm that I have an xbox user who faces the same problem. In fact they see the exact same skin as in the uploaded image from the OP.