That’s what I done the other day & found transmission terrible unless, it was because of where I was, on checking my settings with the fly app v 1.9.0 that said feature was still there, smooth & HD, I know because I checked it & it done the same, meaning did not hold or store the setting for smooth as I did try it, strange, surely wouldn’t be different for iOS, I doubt it,
That’s when I restored from iCloud back up & got my old v 1.6.9 back, I did post the scenario for you too see 
Maybe I should try reinstall again but the feature is still there that your saying has been removed or am I just the only one.
Many thanks