Every time I add fps boost resource pack my skin and cape start bugging out.

Hi! So I found another bug and I really hate this bug, basically, every time I add an fps boost resource pack or client resource pack to Minecraft bedrock, my cape starts bugging out and it splits the cape in half, then when I try a different one like better bedrock it just completely changes my customized skin to Steve. If you can fix this I'd highly appreciate it!