If you have never been bleed free for 12 months then you are not postmenopausal and don't have to keep getting investigated if you bleed beyond 6 months of hormone therapy - that's nuts!
Typically those who are still having endogenous ovarian activity are prescribed cyclical HRT for this reason, however as you are aware, bleed pattern is not the be all and end all, and some women choose continuous for other quality of life related reasons.
The trade off for this, if you are not yet postmenopausal, is that some irregular bleeding is to be expected.
This is not pathological and doesn't require repeated investigation.