Conventional wisdom states that Damage of Time rolls numbers together and displays a tick of damage every half second. E.g. if an ability deals 600 damage over 6 seconds, you'd see roughly 12 ticks of 50 damage over 6 seconds.
I walk around with 1600 life regeneration per second. I regularly see 800 healing ticks hovering over my head pretty much all the time. What'd odd is I'll sometimes see values that are slightly higher. So I went out and took off any gear that might have conflicting properties. No life on hit, no life leech, no thorns, none of that. I had 845 life regen, and rounded up four monsters to smack me around for a little bit.
I saw ticks of primarily 422 and 423. I also saw ticks of 507. Which is 60% of 845. (there were also some other values from the final tick to cap my HP when the zombies went on a wiff streak, but that's irrelevant)
The life is given much more often than every half second, so I see three options :
* the function that aggregate sometime aggregate a bit more than 0.5 secondes. It may be fps-related. Have you seen 40% tick ?
* there is "natural" and very weak life regeneration from vitality
* there is a bug in life per second.
I'd vote for bug personally either with display or underlying calculation (hard as hell to test that though). It being less when you're close to max life would be reasonable as you note, but there's no good reason for it being higher.
What you see and what is happening are two different things. I'm going to guess your healing is actually happening more of than half a second but the total you see is the collective between the last two updates from the server.
So if you get a bit of lag, more than half a second might've happened between your last update and you show 800 regened, then the next update comes right away (since the lag cleared) showing a 200 heal (for 1000 total for that second).
This is a total guess but the most logical one I can think of.