It looks like you tried posting the compiled code from your Maestro, but part of it is missing. It would probably be a lot easier to troubleshoot if you could post your Maestro settings file instead. The settings file will allow us to see more details about how your Maestro is configured, along with your script. You can save your Maestro settings file by selecting the "Save settings file..." option from the "File" drop-down menu within the Maestro Control Center.
What behavior are you trying to get when both sensors report true? From the part of the script that you posted, it looks like when
right_sensor report back true, your script reads both sensors again and then goes back to the "start" label. This means that each time the script cycles through and
right_sensor are true, two values are added to the stack and never used, which will eventually result in a stack overflow error.