I am also having an issue with not just the all of the various bottomless potions but also the generic potion. No matter what potion % I put it at, it just will not trigger. I restart DB after every settings change and after restart I verify they are where I put them before running. It seems to have started in the last day or 2.
Running:
Trinity 2.8.2
Quest Tool 3.4.14
DB Beta 518