Rule not matching on Hazel 5.2.2 but does on 4.4.5?

I have a simple (1 condition) rule watching for the a certain 4 word phrase in a text file.
For context, the folder is in Dropbox and is a mirror of a folder on an ancient Unix Server. The file is actually a printer output spool with some non-standard characters (presumably to tell the printer how to lay it out), but it is readable/editable in a standard text editor (BBEdit).
I do not have more than 1 Mac monitoring the folder at a time, I PAUSE RULES on my new Mac while I check my old Mac will still trigger the rule, and PAUSE on my old Mac while I try & get my new Mac to trigger the rule.
On my old Mac (MacOSX 10.12.6 - Hazel 4.4.5) The rule matches and performs the task
On my new Mac (MacOS 13.4.1 - Hazel 5.5.2) The rule doesn't match, incorrectly stating the contents to be matched are not in the file.
I have tried changing the rule from CONTAINS to CONTAINS MATCH but this doesn't help.
I have unsuccessfully tried running the same rule with the same file in a folder that is not in Dropbox & not mirrored.
Any ideas?
Thanks
For context, the folder is in Dropbox and is a mirror of a folder on an ancient Unix Server. The file is actually a printer output spool with some non-standard characters (presumably to tell the printer how to lay it out), but it is readable/editable in a standard text editor (BBEdit).
I do not have more than 1 Mac monitoring the folder at a time, I PAUSE RULES on my new Mac while I check my old Mac will still trigger the rule, and PAUSE on my old Mac while I try & get my new Mac to trigger the rule.
On my old Mac (MacOSX 10.12.6 - Hazel 4.4.5) The rule matches and performs the task
On my new Mac (MacOS 13.4.1 - Hazel 5.5.2) The rule doesn't match, incorrectly stating the contents to be matched are not in the file.
I have tried changing the rule from CONTAINS to CONTAINS MATCH but this doesn't help.
I have unsuccessfully tried running the same rule with the same file in a folder that is not in Dropbox & not mirrored.
Any ideas?
Thanks