I've been tracking this one down for a while, because its pretty annoying!
On the su-25, if you are using a joystick input for TDC slew, when the laser designator is ground stabilised it adds your planes motion the cursor when you attempt to move it. This does not happen when using mouse input, and it correctly translates without adding plane motion to the cursor
On the su-25T, the exact opposite is true - when using joystick input for TDC slew it works great, but when using mouse input for TDC slew it inherits your planes velocity and adds it to the motion of the camera
Both of these things occur when in ground stabilised mode only when input is entered, and aren't related to any features of the aircraft in any way, its a simple bug depending on what kind of input system you use, mouse vs joystick, and its the exact opposite between the two aircraft
https://www.youtube.com/watch?v=DyjiGAifo7I is a video of the repro