I’m using version 7.3.1 on my new iMac running Sierra 10.12.1 and no matter how I adjust the size it just goes to the max possible size in the application window, and sometimes freaks out (scrolling further and further to the right in the active window) and I have to hit escape to stop it.
This exact same macro worked fine on my old iMac running El Capitan. The same issue happens on both Illustrator and Indesign
It seems to work fine operating on Safari or Keyboard Maestro windows for me (all I tested). I don’t have Illustrator or Indesign so someone else will have to verify whether they have any issue with resizing a window using Keyboard Maestro.
I hesitate to suggest it, but when bizarreness like this happens, restarting is not a bad idea. Especially after a system upgrade I have had cases where the system is not happy until another restart happens.