A chmod +x is added to the run script generated during packaging in StageBootstrapExecutable. I think understand why this chmod is embedded in the generated run script instead of just being set once upon packaging, given these permissions might not be maintained on select file systems(?).
For CARLA simulator users, this results in a red herring when the user runs the script without being the owner of the file (e.g. read-only, multi-user deployments). Is there a way to prevent this line from being added to the generated run script? From examining the UE code, that appears to be no for UE 4.24 at least.