Mcintosh 8900 Stored Input Name Problem

Hi, I have two 8900's and am having the same problem on both units.  I'm thinking it's me as the problem.  When I go through the process to assign a custom name for any of the inputs, it works for a while through power on/off cycles but then somewhere down the road (weeks?) it no longer has those custom names.  Has anyone had this issue or can help rectify it?

Thanks!