Why are my Blender animations showing up differently in Roblox?

I animate rigs using Blender and have recently noticed this issue where my animation can look perfect in Blender and once I import the data and preview it, an arm or a leg or something will be off of what was previewed. The more confusing thing is that it apparently doesn't look like that for anyone else.

Example:

https://cdn.discordapp.com/attachments/553010404247207936/773316131607019540/Screenshot_2.png

https://cdn.discordapp.com/attachments/553010404247207936/773316643110912040/Screenshot_3.png

My only solution so far is to counteract it by putting the miss-shown limb in the opposite direction, but then people have said that it looks weird (probably because it looks like the animation shown in blender but for me, roblox shows it differently).

Anybody know what exactly might be causing the issue?