As you may have already noticed, starting 16.3.1 now all mobs do each a single type of damage instead of switching to chem/en/proj/etc. While this is kind of logical, it also means that now the effectiveness of all Layer effects (including Bio Cocoon) has been cut to 1/5th.
Example: A bio-cocoon worth 3200 layers can absorb 3200 of EACH type of damage before collapsing, so while fighting say, a heckler, that cocoon is worth around 16,000 damage all together as a heckler (as most monster-mobs usually did) switched damage type with each hit, now it seems all mobs do the same damage, so your 16,000-damage cocoon (aprox) has been cut to 3,200, and if you used to last around 6-15 seconds against a heck, you now last 2-3 seconds only.
Was this planned to lower the power levels of the game intentionally, or was this just an unforeseen aftereffect?