First, though, did you know "culvert" seems to be the latest official term for what players have variously referred to as an automata maw, round maw, gold maw, mechanical maw, or (confusingly) pipe? Look at the new Codex item list:
I have to say, I think "culvert" is the best term yet. Certainly way better than "pipe," which is what it was originally called. (You can see from the item ID, though, that at heart, culverts still think they're pipes.)
Anyhow, with that in mind, here's my mass spawner issue:
It seems like if you have a diamond mass spawner configured for active maw spawning, and you kill a maw- or culvert-dropped mob with a crit hit such that the mob drops its loot directly on top of the maw or culvert (instead of into your inventory), this appears to instantly and totally suppress all mob spawning from that maw or culvert.
In worlds without mass spawners, if a mob's loot drop obstructs a maw/culvert opening, a new mob will eventually (usually quite quickly) spawn and consume it. In fact, placing any item on top of an open culvert is a tried and true way to destroy that item. But for some reason on my world with the mass spawner, a pile of resin is blocking the culvert and refusing to disappear.
It seems that actually PLACING a pile of giblets on top of an open maw or culvert also completely suppresses further mob spawning, but only in worlds where mob spawning is activated by a mass spawner.
I have tried leaving the world and coming back, logging out, and quitting the game entirely. That damn resin is still there, ha!
Can anyone else with a diamond or onyx mass spawner let me know if they're seeing the same behavior?
(Below is a snapshot of me waiting hopefully for a mob to spawn and obliterate that pile of resin. Yes, that is my hopeful face.)