Lost 1080p

I was running Kodi in Openelec 6.0.3 with an Intel I3/Intel H55 motherboard. It’s connected to my AVR by HDMI. I just did a migration to LibreElec 7.0.2 by doing manual update in the /storage/updates directory. Everything updated fine but when it restarted I lost the video. I connected a second VGA monitor to see what had happened. The video output was still set at HDMI 1080p/24 but I wasn’t getting any output (the TV displayed “signal out of range”). I tried bringing it down to a lower resolution and it works ok at 1280 x 720p/60. Is this just a bug in LibreElec presently?