OutlinkUrl filtering issue

Hello everyone,
In Segment filtering a url which is having request parameter is given as actionUrl but empty result getting

Eg: case 1. actionUrl=@link=standard is given as segment in this case getting result which contains link=standard

case 2. when i gave actionUrl=@&link=standard not getting result

case 3. also actionUrl=@%26link=standard given but in this case also not getting result.

The actual url is like https://abc.xyz.com/contact/?form&link=standard

filtering with case 1 getting the above url.

method used is CustomDimensions.getCustomDimension