$regexp(%TITLE%,[^0-9a-zA-Z],) does not work

Mac
2

If I try it with the Convert Tag -> Tag (to see the result in the preview - green box) I don't see any error:

image

Could you please show us with a screenshot where do you get the "invalid regular expression" error message?

BTW:
The regular expression itself should be something like
$regexp(%TITLE%,'[^0-9a-zA-Z]', )
to get
image