Is it best to clip your dots when 1-2 seconds remain or let them drop off completely?

Also, anyone else getting an issue where a dot isn't showing but is present on the target?
I've had it happen with Bio II on Archerus and Bio on Behemoth (sometimes Miasma II or Bio II). I kept pressing the dot, thinking I missed but the icon simply doesn't appear.
Then I tried just continuing the rotation and Fester would hit as though 3 dots were present.

So I just assumed it was on, but not showing. It would come on occasionally, then disappear again.
Behemoth is a fairly long fight so I got to experiment a bit. Bio wouldn't show on the target but if I Contagioned then it actually appeared with the increased time.

I'm guessing it's not a coincidence that both these settings have a lot of people?
I know there was a dot limitation before. Maybe it was removed but sometimes the visual doesn't show up.
Sorry if this is a known bug. I just never heard of it.