That version is no longer being maintained, maybe try using Cautioned’s version.
That’s weird, I’m sorry, but I don’t know how to help you other than suggesting the maintained version of the plugin/addon.
This is not a bug though, Roblox uses Y as the up-coordinate but Blender uses Z, this one you’ll need to get used to or change the rotation order in the item tab.
This animation is broken when uploaded to roblox from Blender, I’m currently using Blender 3.6 as I know the latest version has some issues with the roblox animation add on and the animation is in 60 fps. Her is the difference between the animation in blender and studio:
If anyone knows what could cause or is causing this issue I would be really glad to get your help
And delete version of the program by Cautioned
and install the original calmly, using the rig that I attached in the message back Use this Blender addon