Perhaps. @grahamh asked for the logs to gain insight into that issue. I’m sure he will chime in again when he gets the time.
Kind of. If you set your UI to 1080p 60hz and configure a whitelist with only the various 4k refresh rates then all HD and below video that is not matched to 60hz output will be upscaled to 4K. This is because the UI resolution is always included as part of the whitelist. If you have a whitelist and are playing a source that outputs to the UI resolution instead of 4K this can be switched during playback in the video options (this is only visible if you have a whitelist).