I also own a VU+ Duo 2, but only temporarily tried OpenBh 5.4, due to Kodi problems, but didn't experience any problems, with the front display.
I doubt it's a hardware problem, as you state it works normally, on boot up, and I assume after installing OpenBh 5.4.
You can try installing OpenBh 5.3, without adding any plugins, or extras, and see if it works normally, then, if it does, try a fresh installation, without any backups, plugins, or addons, then if it works normally, try adding your plugins, and changes, and see if you can narrow down the problem.