I've been having a problem for quite some time where when I use PageDown to skip to the next page in the guide, it not only goes to the next page, but also jumps forward in time. If it's already forward in time and I hit PageDown again, it might jump back in time, or forward in time again. Behavior is a bit inconsistent. PageUp works fine. I have a Logitech remote where I am basically mimicking a keyboard via a FLIRC USB dongle. I have mapped PageUp/PageDown to some buttons on the remote, but I have ruled out the remote being the problem because the issue also happens if I plug a USB keyboard directly into the streaming device and use the PageDown key.
The issue only happens if a program is highlighted in the guide. If the channel on the far left is highlighted instead, the issue doesn't occur. I have been able to reproduce the issue on a 2019 Nvidia Shield Pro and on the original Onn 4K Pro. Both are running version 4.9.4 of the Channels app. The issue doesn't reproduce on an AppleTV running version 7.1.1 using my Logitech remote, but I also can't quite remember how I programmed my Logitech to do the PageUp/PageDown for the AppleTV.
I found the following thread where the issue was reported over a year ago, but it seems the issue couldn't be reproduced, and the thread eventually was closed out. The last reply was about a year ago.
I have linked to a video showing the problem, including me using the keyboard. Hopefully with the detail information and the video, the issue can be reproduced and fixed.