So when you join a server you can't see anyone.. But if someone joins after you, you can see them but they can't see you.
MC-88688
Can't see other players in 15w37a
Resolved
Duplicate
0
Jere Leukkunen
(Unassigned)
Unconfirmed
Minecraft 15w37a
Retrieved
Thank you for your report.
However, your ticket has been resolved as a duplicate.
This issue has been linked to the original bugreport: MC-88470. You can find or add further information on that report.
Please search before reporting any bugs, as it's likely that one exists already.