Thanks for the detailed report. Drone correctly captures the error, however, there is a minor UI bug where the error is not being displayed as expected which is what you are experiencing. This is a minor regression from 1.x and we plan on fixing the UI in an upcoming release. Lets merge this into the existing thread.
I appreciate the offer . we just hired a new frontend developer and this is one of the first tasks they will be working on. So nothing to do at the moment except wait for a new release. In the meantime, you can use the API or CLI to get the error message if / when you encounter this issue.