This bug affects me as well on Elementary OS Hera 5.1.7 (GTK 3.22.30).
Plank 0.11.89 Dev
I resumed my laptop from suspension and I plugged the second screen on the left.
Now, in order to open plank, I have to move the mouse at the bottom of the second screen: this shows Plank at the bottom of the main screen.
Plank shall open moving the mouse at the bottom of the main screen.
On settings I see "On primary screen: eDP-1".
Toggling "On primary screen" > Setting HDMI and resetting it to eDP-1 "solve" the bug
This bug affects me as well on Elementary OS Hera 5.1.7 (GTK 3.22.30).
Plank 0.11.89 Dev
I resumed my laptop from suspension and I plugged the second screen on the left.
Now, in order to open plank, I have to move the mouse at the bottom of the second screen: this shows Plank at the bottom of the main screen.
Plank shall open moving the mouse at the bottom of the main screen.
On settings I see "On primary screen: eDP-1".
Toggling "On primary screen" > Setting HDMI and resetting it to eDP-1 "solve" the bug