After upgrading or installing JQL Booster Pack into your Jira instance, some filters have stopped working and are unusable.
You are using JQL Booster Pack v1.2.0-RELEASE or higher, in conjunction with 'Script Runner for Jira' , 'JQL Tricks' or another app that also provides new built-in JQL functions.
Some other plugins may provide functions with the same name as those provided by JQL Booster Pack, e.g. subtasksOf() or parentsOf(). For functions like these, no other name would make a great deal of sense, so this is not surprising.
The rules for when that happens are explained in JRA-24219, i.e, the plugin key that is first alphabetically will "win". As the others apps are generally "JQL Tricks" or "Script Runner for Jira", whose key is after JQL Booster Pack’s, you will need to disable some modules within our app, in case you want to still using the function provided by this third-party apps.
To use both apps without any issue, go to "Administration" » "Add-ons" » "Manage add-ons" section, then expand the modules for either plugin, and selectively enable or disable the JQL function modules for those functions. For example, in JQL Booster Pack, the module providing parentsOf() is displayed as: