Apparently you’re not the only one with this issue. https://forums.lr4x4.com/topic/109540-help-with-axle-rebuild-stub-axle-and-drive-shaft-issue/
May need to have it machined out or get Genuine ones.
Wow. What a mess. Mine are RN Proline which, I assume, are Britpart. Shame on me for trying to save $30. Ugh.