Running Beta v107
"Edit in Affinity Photo" work partially for me in Beta v107.
Two other issues with the Photos.app extensions:
-The Affinity editing features within Photos are not functional (Haze removal, monochrome, retouch, etc...). See error in attachment.
- "Edit in Affinity Photo" takes me to Affinity, but if I do not make any changes to the file in Affinity and I simply close Affinity, the photo that appears back in Photos is not the photo I started with. Instead, it will revert back to the most recently edited photo in Affinity via the Photos extension. See video.
* Hardware is all factory issued stock on my machine. No unusual peripherals.
Screen_Recording_2019-01-24_at_8_34.42_PM.mov