It would be helpful if, rather than pushing feature cards into the next release, features appeared as red or errored when they exceed workflow capacity for a release. This way these features that were never manually moved won't suddenly disappear from reports, or inexplicably appear in a later release.
|Release time frame|
The currently functionality is as you had described. Features will stay in release (regardless of whether the capacity limit has been reached). However, it is graphically displayed to show which features are beyond the limit.