Lingering potion bug

Checked only in snapshot 15w47c

When you are trying to drink potion of x while you are in last second (maybe two last seconds) of effect of lingering potion of x this effect will stay in 00:00 duration for a while. Drinking milk gains nothing nor clicking escape.
In this case night vision generates fast blinking screen and fire resistance is still working for a while (when I walked into a fire, effect of the potion was quicly removed [maybe it was updated/checked and removed propably because effect with 0 duration cannot exist])
I checked this bug with night-vision and fire resistance.

I checked it only with lingering potions (first lingering and then drinking).
With /effect for few secs it doesn't work.
I haven't checked spalsh potions and drinking potions (too long duration ).

Sometimes effects of lingering potion are restored to twenty something seconds with (no?) reason. It was during my tests.