If there's some kind of urgent issue, we have no issue making a bug fix release, but in this case the issue mentioned was only brought up by two people so it's just not an urgent issue.
Practically speaking, as FOSSBilling matures and becomes more stable, releases will likely become less frequent as the focus shifts from fixing bugs and refactoring old code and instead to improving what's already there and adding new features.
Right now, we are still fairly early in the bug fixing stage, as despite having well over a 1k commits since forking from BoxBilling, there is still a lot of old code that has gone mostly untouched since BoxBilling and still suffers from bugs and poor quality.
Not to mention, we are still below version 1.0.0, which is where we will consider FOSSBilling to be production ready, and at that point we will likely have both "beta" and "stable" release branches, and make beta releases a few weeks before we make "stable" releases, so people can easily test for newly introduced bugs before an update goes live.