My vanished player shows up in every single voting website in which players are listed, also in my Enjin online players box, and also shows as an extra player on the servers multiplayer player count (I think this was fixed?).

The obvious result is, players can know if anyone is in vanish just by checking these lists.

Any way to fix this?

Your enjin plugin shouldn't be sending that info. Request that feature of the Enjin folks

Not really. (Response to last line).

Ok..., I could stop the vanished player from showing up on enjin website just by insisting... but the problem isn't just Enjin, it's also various voting sites connected to my server where a list of online players appears.