When using the iOS client to work on our 2012r2 server, I noticed that the clientside cursor (arrow) is drawn approx. 2 pixels off to the down and right compared to where it actually registers server...
To be more specific, I am using RD version 10.4.0 (5155) on an iPhone SE (2016) on iOS 15.5. I am using cursor mode (dragging the cursor around using the touchscreen).
^ Here is how it looks when I drag the cursor all the way to the top left in fullscreen, and then how it looks like when I do it in zoomed-in mode. The cursor is rendered 4 pixels down and 4 pixels to the right (8 and 8 when zoomed in) of where it physically is serverside.
^ Here is where the desktop icon hitbox registers when slowly moving the cursor upwards. Again, when zoomed in, the cursor is drawn 4 pixels lower (8 in zoomed screen) than it really is.