Lightroom Classic no longer offering to create proof copy during soft proofing

Previously when in soft proofing mode in the Develop tab when I started to make any adjustment to an image an automatic pop-up would appear asking me if I would like to make a proof copy.

This no longer happens, and now if I want to create a proof copy I have to click the Create Proof Copy button under the histogram in the top right.

I don’t know when this stopped working or if it was following a version update.

I have checked and done all the following to try and fix this:

• definitely not working already on a copy
• the Reset all warning dialogs in Preferences is greyed out suggesting there are no prompts to reset
• reset preferences by removing preference file from folders

Any other suggestions greatly appreciated for how I can get this auto prompt back.