Hi Steelbule,
When the bgp ignore command is used, the device sends a notification message first, and then the BGP peers send ACK messages to each other through TCP.
The process is as follows:
1.1.1.1 establishes a BGP peer relationship with 2.2.2.2 and then the bgp ignore command is used.

The notification message is sent first.

Then 1.1.1.1 sends an ACK message with the fin bit set to 1 to 2.2.2.2.

In the end, 2.2.2.2 sends an ACK packet to 1.1.1.1.

Thanks!