Person Attribute Type - Move Up / Down Throws Error

Demo Environment - OpenMRs->Administration->Manage Person Attribute Types->Select a person attribute and Move Up / Down

Throws the following error:

This error is also reproducible on 0.91 -

I think this is happening in openmrs 2.1.x and beyond (and not on 2.0.x). I can replicate the same on ref-app which has 2.1.3

@darius @dkayiwa

Caused by this:

Thank you @dkayiwa .