Regex in Web Reports failing

I have a regex in my Web Reports that kills my reports. I can run this in the Relevance Debugger with no issues, but when I put it into the Web Reports it just dies.

Has anybody had any issues with using relevance similar to …

(minimum of (((day_of_month (parenthesized part 3 of it as integer)) & (month (parenthesized part 2 of it as integer)) & (year (parenthesized part 1 of it as integer))) of (matches (regex "(\d\d\d\d)-(\d\d)-(\d\d)") of "2015-11-29")))

… in their Web Reports?

Do I need to escape the regex somehow that I am not seeing? I tried escaping the “” but it didn’t seem to matter.