I found an issue with Field Rules.

When I have two fields with a similar radio button value, for example,

• I / We request that the pneumonia vaccine NOT be given.
• I / We request that the pneumonia vaccine NOT be given, resident received vaccine prior to admissions

When I want to show a date field when the second value (I / We request that the pneumonia vaccine NOT be given, resident received vaccine prior to admissions) is selected, the date field appears when I select either the first option or the second option. 

I had to assign different values to each choice for it to work.

But, it looks like Forms has a limitation with its compare function.