With multi-selects you want to use the Contains operators, but if you need to match for multiple values you'll need to use REGEX as you're already doing. It's likely the reason it's not working could be due to a bug as you're 10 bug fix releases out of date.
CB Conditional:1.8.0
You've quite a few version out of date, please upgrade. Latest is 1.8.10 and 1.8.11 should be released today or tomorrow.