Coordinated motion with encoders

Assuming I perform a coordinated move involving two axes, e.g. G1 X1 Y1, and the X axis has issues keeping up (position measured with encoder), would the Y motion slow down such that I still get a perfect 45 degree?

No, you would get a X axis following error fault

Thanks for your quick reply. So only rigid tapping is the only truly synchronized motion?

Rigid tapping, threading, general spindle synced motion (G33)

Of course axis motion is synchronized but in a top down way