This question may be related to a resolved thread.
We upgraded to 2.2.1 last week. Everything was working ok. This morning we needed to set debug level to 2 in the CP momentarily. Now we are unable to go back to getting JS {} to be outputted correctly even when we set the debug level back to 1 on both the CP and the config.php file (it was 0). In the meantime we are using debug level 2 on the CP which works fine.
We downloaded 2.2.1 files after the hotfix had been applied. Just in case we also downloaded the hotfix and replaced the appropriate files, but no luck.