Edited Filter showing photos that are Unedited

For years I've used the filters to only show Edited images prior to exporting for a quick and easy selection. Recently (the last 2 months or so) I've noticed there are images that are registering as "edited" in the filter that I've never touched. Often times there is a slight color temp difference but none of the develop sliders are modified. It's only a few (10-15) images that do this but it happens across multiple catalogs and collection sets pretty consitently but without any reason I can see for them to be defined as edited.