I've noticed some odd with mana regen, and I've only seen it on Twisted Treeline. Obviously, when I use a spell with a mana based champion, my mana regen per second appears in the mana bar. But for some reason, as my current mana approaches maximum again, my regen per second actually decreases by .1 constantly. In the end, if I had half mana and didn't use a spell till I reached full, I'll end up losing almost 2 whole regen per second. While it's not a HUGE change, I know it doesnt happen on any other map, and i don't remember that being a function of TTL. This has happened to a few others I know too. Can anyone explain this to me or know why?

There is a map-wide passive buff similar (but stronger than) Chalice of Harmony on the new TT. Hopefully they add a buff icon like in Dominion as it is rather important information.

There's a weak Chalice-style buff that affects mana regeneration. I'll add it into the altar tooltip for 1.72.

Ah, thank you, that explains it. Was just concerned when I saw my mana regen lower and I'm playing Brand XD.