New bnhf/olivetin:latest (aka bnhf/olivetin:2025.07.09) pushed today with a change to the way the Standard Error output and debug information are treated.
The original idea was for users to view output from a particular Action in Standard Output, and to leave Standard Error closed unless there was an issue that required deeper inspection. However, a fair number of users that have posted in this thread appear to have both types of output open at all times.
So, what I've decided to do is to redirect debug output to a specific file for each Action. That file can now be viewed, when needed, using its own Action. This way, if there are no actual errors, Standard Error won't even show as an option.
For example, with the OliveTin Post-Install Healthcheck, note that there is no Standard Error section to expand:
If you'd like to look at the debug output for a particular Action, or if you want to post it (being aware of possible sensitive data in some debug output), you can go to this new Action:

EDIT: Forgot to mention this change also has a positive impact on what displays in the OliveTin Portainer log. It's no longer a mixture of Standard Output and Standard Error (which was almost always debug info). Now it's Standard Output only, resulting in a much cleaner looking startup log.