With the BUG mod, I always(?) get a bunch of unhandled Python exceptions upon reloading scripts, and then part of the screen may not get updated properly, Advisors may become inaccessible, will need to exit and restart (screenshot from BUG 4.4 attached; reload caused by a change to CvMainInterface.py). So, as far as I can tell, editing scripts at runtime isn't really possible with BUG-based mods. In AdvCiv, I've gotten things to a point where reloading will often succeed, and, when it doesn't, making another change (to the same script, or maybe a different one), will usually do the trick. But I don't know enough about Python and the BUG design to fix this properly. A bit strange that BUG introduced those issues; as a Python-only mod, you'd think that its creators themselves would've been greatly inconvenienced.