I have and issue with using the 'SHIFT' constraint to place elements vertically or horizontally. Sometimes, the constraint puts the object just off vert. or hor..The off angle is around 1 degree or even less and it is often too close to notice. It is only when one aligns it with something that is correctly hor. or vert. that it is noticed. Then, it seems to fix itself, until it re-occurs - usually unwittingly. I've had this happen in many recent versions including AC19.
Cornelis (Kees) Wegman
cornelis wegman architects
AC 5 - 26 Dell XPS 8940 Win 10 16GB 1TB SSD 2TB HD RTX 3070 GPU
Laptop: AC 24 - 26 Win 10 16GB 1TB SSD RTX 3070 GPU