Hi!
The layer context menu from the Layers panel offers a row of colors at the bottom which can be used to assign color tags to layers. However, saving a layer composition with color tags applied as a snapshot and then restoring that snapshot will result in the removal of all color tags from the layers – either because these don't get saved with snapshots or because loading a snapshot deliberately resets all layer color tags for some reason.
This is not a new problem with the 1.8.4 updates, I just didn't have time to create this topic earlier. Also, although I posted this in the Affinity Photo Bug forum, the problem is reproducible with Affinity Designer as well. I'm on Affinity Photo and Affinity Designer 1.8.4 under macOS 10.15.6 Catalina. I don't know if this has been reported before, but a quick forum search didn't bring up anything related.
Cheers
kaffeeundsalz