New features only come out in X.X releases--9.2, 9.3, 10.0, etc.
9.2.7 is a maintenance release. Maintenance releases are only for bug fixes. The bug in question here either doesn't exist in 9.3 or will be fixed in 9.3's next maintenance release. Most likely the bug isn't in 9.3--development would have been aware of the bug in 9.2.6 before 9.3 was released. The reason for the "parallel tracks" is that some customers aren't always able to upgrade to the next major release right away. So they stay with an older version but still get their bugs fixed.
The dates of a feature release (x.x) and a maintenance release (x.x.x) are not related in general. Like Andrew said, they are two parallel tracks. However, the development organization at Tableau takes bug regression very seriously. For any bug that is reported on a certain release, we always forward integrate it to newer releases, including feature release x.x. Often time we apply the fix in older release(s) as well depending on the defect's impact to our customers.
Having said that, if you have a salesforce case number, or can provide a description of the bug you reported, I can double check the code base and let you know for sure.