I know this was brought up in 2018 but for me it began with Cubase 12 and is still broken in 13, so more than two years… IIRC it started happening in C12 when I switched to an M1 Macbook, but I might be wrong.
Basically I can’t pitch downward with time correction, not with any algorithm - UNLESS I use the envelope function and create a straight line, as a work around (see video). It also works fine with transposing in the Info Line, all algos work.