Raiders stay near an ominous banner which they can't pick up

If you push the leader of raiders into the nether portal during the raid and throw out an ominous banner, the illagers will all stop what they were doing and try to pick it up but can't. They end up all staying near the ominous banner and doing nothing else.

Sub-bug: If you reload the save, pick up the ominous banner and throw it out(Or you can just leave the ominous banner you threw out there). An illager can pick it up and become the new leader.

Steps to Reproduce:

Step 1: Trigger a raid.

Step 2: Push the leader into the nether portal.

Step 3: Throw out an ominous banner onto the ground.

For Sub-bug:

    Step 1': After finishing step1,2 and 3, save the world and enter again.

    Step 2': Pick up the ominous banner and throw it out. (Or leave the ominous banner you threw out before on the ground) 

Observed Results:

Illagers all gather around near the ominous banner and try to pick it up until the item disappears. They all stop doing anything else but just stay there. And they won't attack players even if players attack them.

For sub-bug:

    An illager gets the ominous banner threw out by the player and successfully becomes the new leader.

Expected Results:

Illagers ignore the ominous banner dropped by the player and continue attacking players and villagers.

Screenshots/Videos:

See the attachment files.

For sub-bug: See 2022-10-27_20.09.27.png

Notes:

This bug and its sub-bug can be confirmed in 1.14 - 22w43a.