Steps to reproduce
Create 2 large, sealed rooms 20 blocks apart from each other.
Inside each room place 3 beds each 15 blocks apart from each other, and spawn 3 villagers.
Place a bell at the far end of one of the rooms.
Set the time too noon and wait for the afternoon gathering.
Expected results
The villagers in the room with the bell gather at the bell, and the villagers in the other room do not.
Actual results
The villagers in the room without the bell get angry that they cannot gather at it. That causes the villagers in the room with the bell to lose their links to it. A cycle of linking and unlinking ensues every day at gathering time, with the final result that the villagers who could gather at the bell fail to do so consistently.
I have about 40 villagers, 6 of which are close to the bell, but they won't mingle during mingling hours. Rarely, they'll talk for a very short time, but as other far-away villagers try to link to the bell and fail, they'll stop mingling and wander around aimlessly.
Comments 3
I tried placing multiple bells, and the same result occurs: As other villagers try to link to the bell and fail, it seems to cancel out mingling during mingling hours. Even if I place bells on each of the sectors for the various villagers, they don't seem to mingle if other villagers can't reach that specific bell.
I removed my last comment because after thinking about your point I think this issue may be beyond the scope of what was originally considered in the report about beds and workstations (MCPE-45270). Bells present a complication because multiple villagers link to a single bell, and therefore a single stuck villager can break the links of all of the others.
Only 20 villagers can link to a single bell. Since you have more than 20 villagers, you'll need to place another bell to ensure that they all try to mingle.