washing machine switching quickly between hot and cold fill

Hi. I have an old Kenmore 80 series toploading washer that I bought refurbished. The hot has always filled a little slower than the cold, as far as I can remember. Yesterday it stopped filling with hot altogether and would do cold instead. Today when I went to start a load it started filing with hot (was on the Hot/Cold setting) but then began switching between hot and cold. I have the cold line split between the washer and the CatGenie (self-cleaning litterbox) and noticed that the switch seemed to coincide with when the CatGenie ran water (the washer switched to hot when the CatGenie ran its cold water).

I am mystified by this. I know next to nothing about washing machines. Is there something about the change in cold water pressure that could be causing this? Why would it happen suddenly? The machines have been set up like this for months, no problems.

I thought at first (before it began doing the switch thing) that maybe I had a clogged inlet screen and was going to investigagte that but haven't yet. Could it be related to that? Or is this likely some sort of electical/switch issue?

Thanks for your help!

 

Clogged inlet screen in washer fill valve might cause this or low water pressure to washer. Take the cold water hose off at washer and inside valve end is a screen that will come out. clean screen and reinstall.