[2020] Questions Thread - June 11, 2020

An enemy can only be affected by one Bleeding debuff at a time (whichever is strongest). That is entirely unrelated to where the debuffs come from, it's part of how bleeding works (and most debuffs in PoE follow the same rule, and exceptions are generally called out).

Burning is not a specific debuff, but a category which refers to any form of fire damage over time. Individual debuffs that cause burning will have their own rules.

Decay follows the standard debuff rules - if multiple are applied to the same thing, only the strongest will affect them.

My question is more aimed at what happens in game logic when Bringer is unusable due to stat insufficiency, re-enabling the chest

That doesn't happen. Bringer of Rain doesn't grant you a stat that disables the chest slot like a normal, sane item, it has a stat with special handling in the disable scan code, such that it will continue to disable the chest slot as long as Bringer is in the helm slot, even if it is itself disabled.