I was getting this same issue with version 2019.2.618.40 and have fixed it with some of the information in this post.
1) I ran the Upgrade Wizard in the Telerik UI for Winforms menu (even though the project was already upgraded).
2) Received a screen showing 0 errors, 0 everything. It basically seemed to do nothing.
3) Chose Build, Rebuild Solution and let that run.
4) Closed out of Visual Studio Professional 2017.
5) Restarted Visual Studio.
6) Opened the project and then I was able to "Open Property Builder" for any GridView.