Ontapp Tv black screen epg

I’m experiencing an issue with Ontapp TV using Kodi Krypton on an Nvidia Shield, which doesn’t happen using Kodi Jarvis on the same device. While I’m watching a programme via my HDHomerun through Ontapp TV, and switch back to the guide/ picture in picture mode, the epg screen is totally black. All channel logos have disappeared as well as other interface details. When I stop the channel playing, the epg interface returns to normal. Disabling mediacodec (surface) solves this problem, but also makes video unstable, so not an option for me. Ontapp developers suggest it’s an android bug in Kodi 17. Any support would be appreciated. Thanks.