The regex in _parseFieldsFromViewFile() that detects script-based params is malformed and detects incorrect matches.
It detects param ... name= - and continues to the next semicolon. However, this matches the script-based tags too, up to the next semicolon.
So, for example, this:
will have the following matches:
... and in turn, these matches will cause the previously-set fields to be overwritten and misconfigured - for example, changing the fieldname or renderer - with unpredictable results.
The solution is to ensure that if a > is encountered before the semicolon, then the regex does not match.