Happened this morning, screenshotted but thought it was a one off so thought nothing more. Just had the issue again a few minutes ago whilst flying (didn't take a screenshot as was trying to be quick to avoid being mugged).
Just fyi, not sure if it might be triggered somehow by switching between devices. Both times it happened was a very short time (within a few page clicks) of moving from mobile device back to desktop. Unsure if that was just a coincidence though.
Thanks