Rig keeps reverting to one particular position/pose

My rig keeps reverting to this pose, especially after exporting. This problem propagates to Unity, where the model makes the pose as well. I have tried resetting the rest pose, but this hasn’t worked.
Any ideas on how to fix this?

Thanks in advance.

Looks like you have keyframed the position of the bones. At frame 1 this is the pose you have keyframed.

Thank you for the reply.