I am having this exact same issue - and with a script that's been working for years. All of a sudden the method in the script isn't recognized by Pega Robotics. Please advise as to the possible cause and a fix for this issue.
Make sure you have script and global container (where script is located) opened in Studio and checked out for edit (if you use source control). Then, add new method, rebuild project and you should see that global container has unsaved changes (* symbol to the right of container name). Save all and then check if method is visible now.
If it still doesn't work, please post your script here.
Did anyone figure out why the scripts are not displaying? I have exactly the same issue with some new scripts I wrote. The scripts are in a global container immediately below the project level. The automations are also in a folder under the project level. I have successfully validated the scripts, and then cleaned and rebuilt the solution. I still cannot see the script names as methods under the script objects in object explorer.