did you find a solution to this issue?
i have a similar situation
If setup Conditional Formatttion using any letter \p{L} -- it ends up falining -- ie. field1 matches pattern \d\d-\p{L} (then hide a section)
test it in preview and workd fine!
However, Then in design mode i switch views then go back to that conditional formatting -- it reads: field1 matches pattern invalid pattern
now the formatting obviously fails
apparently there is a bug of sorts when using \p{L} in condition formatting
has anyone seen this or know of a work around??