Hi Jon, sorry it took me so long, but this issue is a bit difficult to track down.
I had the mentioned behaviour some minutes ago again and was not able to resolve it without eventually renaming the script file.
The last time I tried it worked as expected, but once it get's into the problematic behaviour it keeps malfunctioning for some unknown time.
I think it has something to do with the script config getting out of sync with what DO remembers and/or the defaults a script uses/used.
I uploaded the script here, but I doubt it's going to show the same error for you, if you freshly put it into the scripts folder.
Thanks for all the other fixes in 11.7.2, the uploaded script makes use of the new "right" property e.g. (with a fallback for pre 11.2.7).
cya! o)