Confirmed on current MaNGOS Zero.
Tested on a naked level 60 Paladin with no gear, no talents and no extra buffs.
Holy Light Rank 4:
- without +healing: 350 / 368 / 339
- with +1000 healing aura: 780 / 773 / 777
The actual gain was about +424, which matches the 1.5 / 3.5 minimum cast coefficient instead of Holy Light's expected 2.5 / 3.5 coefficient.
I submitted a fix here: https://github.com/mangoszero/server/pull/309
After the fix, the same test gives:
- Holy Light Rank 4 with +1000 healing: 1057 / 1076 / 1056
The gain is now about +714, matching 1000 * 2.5 / 3.5.