The first time I logged in as my main toon in Season 7, I saw that my keybind mappings (the small white text indicators in the upper left corner of each tray slot) were all hosed. Some rows of tray slots no longer show any mapping at all; others only say A1, A2, A3 etc. which I presume are the default bindings.

To make matters worse, using the /bind_load_file chat command to try and restore my keybinds from saved files had no apparent effect - the tray slot mapping indicators did not change.

Only by accident did I later discover that my intended keybinds are actually still in effect - only the indicators themselves are hosed. So, it's not as great a problem as I had feared, but it's still confusing enough to be a significant one.