I tried the same today following the exact same steps.. Things continued as follows:
16) Saving everything, publishing localy, closing the engine
17) Verifying file integrity via steam (for both engine and game)
18) Now I was able to set Use Action value of my root template to my new skill
19) Copied ID of the root template
20) Entering the stats editor I noticed the engine updated since there were new entries available (like talent requirements)
21) Opened the custom object stats file to paste root template ID within the corresponding column of the skillbook
22) Since then double clicking the root template column to paste the ID crashes glasses
I restarted the computer, verified integrity again, reinstalled the divinity engine 2 data dlc.. Everytime I want to edit the root template column within a custom object stats file glasses crashes. In existing mods as well as new mods.
I added some new cross class skillbooks and edited said root template column for multiple objects a couple of minutes before I started with step 1)
Don't repeat :o