Setblock command on observer fails if another observer of the same type is present, but observer still sends an update

Was able to test using MC-191016.

Running the command

/setblock {X} {Y} {Z} observer

on a block that is already an observer shows that the command failed to run (either through the chat or the command block output). However, a redstone pulse is sent out from the observer (MC-191016), implying that the block was actually changed.

The expected behavior is that the observer would not be updated when the setblock command is reused on the block (as the command resulted in an error).

I'm attaching a short video of this bug.