1.13.2 Repeating command blocks fire twice when power source destroyed via setblock

Setting the command blocks up as shown in the attachment, and placing a redstone block on top of the repeating command block, should theoretically result in the output:
A
B

in the chat.

What is actually produced is:
A
B
A
B

Is this intended? It doesn't seem like it should be that way...

 

Attachment image taken with positive X going left and positive Z going up