When I transcode these recordings for my vault, I've chosen, for a while now, to de-anamorphise it; that is, to a square-pixel 1920x1080 aka completely standard 1080p. So in a *sense* it's upscaling; from 1440 to 1920 pixels horizontally, but only up to the actual *display* resolution of the video. It's not like I'm trying to turn SD content into HD.
This resolves a few media player niggles (thumbnail generators not respecting the pixel aspect ratio of anamorphic videos, indexers misidentifying the video size (a 4:3 aspect ratio programme, with the black bars cropped off, results in a 1080x1080 *pixel* video, which is identified as 720p instead of 1080p) that sort of thing) and *maybe* makes the transcode itself slightly less lossy.Anyway, I want to carry on doing it.
Now, the *linux* version lets me. I have a preset that's closely based on the standard High Profile preset, that just has anamorphic: none (and a couple of unrelated changes) and that does what I want; emitting 1920x1080 videos.The Mac version won't let me do it; it's impossible through the GUI to raise the number of pixels in the encode. If I set anamorphic to none or if I export the preset that works on linux and import it into the mac version, and try loading the same sort of file, it duly turns anamorphic off and would encode a video of 1440x816 if I let it; thus downscaling which I definitely don't want to do.
I'd just like Mac Handbrake to be like linux and give the freedom to upscale even if it *is* pointless in some situations.
Even if it only allowed it up to the original *display* dimensions of the video, that would resolve it for me. And please, because I've drawn your attention to the different behaviour, don't instead make the linux version behave like the mac version does now, because I'll have to stick at the last version before you do that forever 
NB: This is using nightlies on both platforms.