BungeeCord arm glitch

Hi I have a Bungeecord server with the hub being 1.12.2 and kitpvp being 1.8. When a 1.12.2 player joins Kitpvp then goes back to Hub. The Arm changes to the opisite side so from right to left. I don't know whether there is a post similer to this as ive been searching on the internet for 3 days now and havent found anything so if you can help i would be very gratefull. Thx
Also if you want to see for your self join frankimc.ddns.net with a 1.12.2 client.