If you recycle templates sometimes it helps to remove all MIDI data as well.
I have had similar problems. And if this occurs it seems there is sometimes a slight alignment issue with the dynamic mark as well. That indicates that the dynamic isn't tied to the note but to the measure. Be consistent in this. I always add dynamics to the note. That helps Human Playback to interpret as I do. If that doesnt work I add an hidden dynamic marking to the 2nd note as well, that sort of helps finale to understand what I mean and somewhat improves the imbalance.
Another thing to note is the use of long notes. Human playback adds a natural decrescendo to long notes, but sometimes seems to forget to set the volume to normal when the long note is over. When I see this I often add an hidden dynamic mark to fix this.
The ultimate solution is to disable Human Playback. But the result gets really square. :(