Hi,
The issue was indeed the first custom code, it is no longer needed for version 4.11.5. I have deactivated it in that custom plugin file. On the back-end I have changed the advanced title field to this: https://i.imgur.com/2Ju8u4r.png
It will display the price with currency, as well as it should respect WCML too. Make sure to clear your site cache, and the search should work now as before.