Some components have become temperature sensitive. These monitors are very complex, and consist of many processing boards. The problem can be where the display addressing or in a number of other areas.
You can start by troubleshooting it with a heat gun and some freeze spray (liquid air) heat the suspected areas and cool with the freeze spray. When you get the area that is making the problem, you can then know what board to swap.
The boards used in these monitors are considered non serviceable. The parts employed are all high density surface mount, and there are also some embedded technology used. If the problem is with the display unit itself, then the complete display would have to be replaced.
When installing a new board, sometimes there are service set-ups that have to be done, which require the service manuals, and the proper tools. This takes an experienced service tech to proceed with this.
You would be best off to give the monitor out for service to the manufactures service rep.
Good luck!