@Mr.H
The plug is not harassing anything, it is telling your computer that it closed the session initiated by the computer.
The plug is combining two packets similar to SYN/ACK data packets.
Here is another explanation:
Once the connection is established, all packets need to have ACK set and match the sequence number of the received packets for reliable transport/security. RST without ACK will not be accepted. When one side sends RST, the socket is closed immediately and the receiving side also closes the socket immediately after receiving valid RST. It does not need to be and can't be acknowledged.
After TCP handshake
A --->B Syn=x, Ack=y, len=z, ACK Flag
B --->A Syn=y, Ack=x+z, len=o, ACK Flag
A --->B Syn=x+z, Ack=y+o, len=p, ACK Flag
B --->A Syn=y+o, ACK=x+z+p,len=q, RST, ACK Flag
B closes the socket after it sends the last packet and A closes the socket after it receives it.
(not considering TCP window here, or there might be more packets from one end before the acknowledgment)
ACK Flag, acknowledgment number, and the procedure of acknowledgment are related but not the same thing.