Skins not instantly changing and some players have their old skin

[Mortem420]

I hope that it's alright that I submit 2 problems in this issue ticket

What behaviour is observed:

Problem 1: Changing skin doesn't happen instantly. Relog is needed

Problem 2: Some players have their old skin. Resetting skin doesn't seem to solve this issue as it just sets the same older skin

What behaviour is expected:

Problem 1: Skin change to happen without needing a relog

Problem 2: Players should have their own current skin when they don't have a custom skin selected

Steps/models to reproduce:

Problem 1: Any action that changes skin

Problem 2: Join server that has ChangeSkin plugin installed

Plugin list:

Spigot:

Environment description

BungeeCord version git:BungeeCord-Bootstrap:1.16-R0.5-SNAPSHOT
Spigot version 1.12.2
Using MySQL

Plugin version:

V3.1 build 242

Error Log:

Hastebin / Gist link of the error (if any)

Configuration:

Hastebin / Gist link of your config.yml file

BungeeCord config: https://gist.github.com/Mortem420/e589fed3d3c93dea0223515daa9b0c35
Spigot config: https://gist.github.com/Mortem420/630fba53bb216c1f58ae7f55fcae8b92