can be a lot of reasons. Please share the blend file. It can be a simplified one - it just should replicate your problem.
If you cannot upload here, just use any cloud service and copy the link.
Here you go
shuriken.blend (119.2 KB)
thank you.
i am not sure, how you wanna turn it, but if you e.g. just wanna have a z-rotation, go in graph editor, select x rotation, press x to delete, select y rotation, delete it. result:

hope it helps.
Oh, I see! That makes a lot of sense now. Thank you so much for clarifying. I found it very helpful.
you are welcome
