This seems like a simple use-case to me, but I can't sort out why it's not working out.
I have a folder which is a dead-simple use-case for the Counter function. I'll periodically drop one or more files into the folder and each file will have an arbitrary name, and I want them to be renamed (this is for Plex, but that's irrelevant to the issue).
Here's the rule for the folder:

Here's configuration I'm using for the Counter:

Here's the result:

The counter isn't counting, and I'm banging my head into a wall to figure out why.
If I switch the Counter's flag from "Use lowest available" to "Always increment" and try again, it somewhat behaves like I expect, naming the files with an incrementing number. Unfortunately, if I pull all the files out of the folder, rename them, then add them back in (even one at a time) I can't get the counter to reset to '0'. And if I then switch the flag back to "Use lowest available", all files get the prefix "E001 - ".
Not sure how to get the behavior I expect, which is the behavior described in the docs. Anyone having better luck? Anyone able to point me in the right direction?
Hazel 4.3.3 on a brand-new MacMini running 10.14.1.