Color label doesn't apply to multiple pictures in filmstrip when in Loupe View

I use color labels to denote what pictures need future processing. Green photos need to be panorama merged, blue photos need to be stacked for astrophotography, yellow are HDR merged. When I'm culling from a shoot I'm in Loupe View most of the time using the flag system to denote edit/no-edit pictures. A lot of my shots are single pictures, but I come across sets of images that need to be marked with green/blue/yellow and then grouped.

When in Loupe View, if you select multiple images on the filmstrip and then hit "8" to mark them as green, only the first one in the selection set gets marked as green. However, when I switch to Grid View, hitting "8" does mark all selected photos as green. Interestingly, if I'm in Loupe View and I right click on a picture in a selection set and set the color label, that will mark all of them as that color label.

It appears it's something in the keyboard shortcut that doesn't allow this. Would appreciate clarification on if this is a feature not a bug. Current workaround is to switch to Grid View each time I need to group things, but that gets tedious when I'm working through a 10k image set (just got back from 5 months on trail, so so many panoramas and astrophotography sets to process).