Faulty breaker? Older than the others?

Why not swap breakers 20 and 22 to see if the problem moves with the breaker?

Shut off the main breaker and remove the panel cover. You can disconnect and swap the wires from the two breakers without moving the breakers.

You should replace the panel cover as your test is going to take several days.

If breaker #19301 trips in position 20 then it is obviously bad. If breaker #20033 trips in position 22 then you have a difficult problem in circuit 22 -- probably a loose neutral connection.

If neither breaker trips after several days then breaker #19301 is faulty (but circuit 20 does not apply enough load to trip it).

EDIT in response to OP's comment about switching the wires without changing changing the breakers:

Actually, what I would do if this was my house, is disconnect the wires but not move them, then physically swap the breakers, then reconnect the wires to effect the swap. I didn't suggest this at first because it involves more steps and is more tedious to describe.

• Turn off main breaker, remove panel cover.
• Disconnect circuit 20 from breaker #20033 and circuit 22 from breaker #19301. Avoid moving the wires as much as possible.
• Pull both breakers from the panel, swap their positions, and replace them.
• Connect circuit 20 to breaker #19301, and circuit 22 to breaker #20033. All the wires should be exactly where they were before you started.
• Replace the panel cover, turn on main breaker.
• Wait for something to trip.

Now nothing has changed but the breakers. If the problem does not move with breaker #19301, then it could be in the panel bus bars behind the breaker, or where the neutral from the breaker connects to the neutral bar, or in the neutral connections somewhere in the run to the kitchen, etc. But you will know that you don't need to buy a new breaker.