Is it normal for the night vision potion to have a faster timer while the scuba tank is giving you air?

"Any potion effect will instantly stop once you equip the Gas Mask and turn on the oxygen supply."
So yes it's a feature.

well it doesn't stop, the timer just goes faster

According to aidan, this is intended, and at one point it may have removed them instantly but we agreed that it just making the timer goes faster makes more sense anyways.

cool, good to know, thanks!