Possible bug with "In" filter

I am using SQL Reporting service 2012, and have discovered that when filtering a dataset using the "In" function, there appears to be a bug.

You are required to put quotation marks around each expression, eg: "Total", "US", "Canada", "Mexico"

At first this works fine, but if you edit the dataset properties, then press OK, the quotation marks disappear, eg: Total, US, Canada, Mexico. Now the report does not work.

If you edit the dataset properties again (without re-adding the quotation marks), the filter reappears with triple-quotation marks, eg. """Total""", """US""", """Canada""","""Mexico""". This also does not allow the report to run properly.

Is there a fix being worked on for this, or has anyone else seen this problem?

Thank you