Short answer, yes, I've checked.
Long answer: I do have two copies of the script, one in ~/Library/Scripts/ and one buried under ~/Documents/, so it is an issue that I'm directly aware of. Because of that, I've sometimes added a dialog announcing which version is running to the start of the script and I think I have that under control. However, you have prompted me to upgrade my script (both copies) so that it displays the source path using "path to me" instead of a manually maintained string.
The result: I made a small typo while making the edit (a space missing from a text string). Right now, both versions of the script file (including the one indicated in the Trigger pref pane) have the typo corrected (as viewed in ScriptEditor), but when I actually run the Trigger, I see the message that still includes the typo.
It's occurred to me that the caching may be happening in macOS rather than in Quicksilver. But that doesn't get me closer to a solution.