This doesn’t look like burn in. Burn in is related to persistent images actually wearing out pixels in a distinct pattern/shape. You see it on TV’s that stay tuned to the same news channel, or displays that put the same content in the same spot 24/7 for many days.
Considering the “burned-in” image is clear, distinct, shows dynamic content, and is exclusively blue, this looks like something between the firmware and the hardware stopped updating the blue sub-pixels, but kept updating the red and green.
Has anyone tried to “cold boot” their monitor by power cycling it to see if the blue image goes away, and functionality returns to normal? Completely unplug the monitor, wait 30 seconds to a full minute, plug everything back in and try again.