Yes I do and I hate that indeed. Most of the time I don't end up dropping the combo but doing a shorter, less-damaging one instead because I have to quickly improvise something.
I do too. I don't drop the combo per say, but when I derp for that second, I have to quickly do something shorter but quick that comes to mind. Thank goodness it doesn't happen all the time...
Another annoying thing I do is wall slam my opponent and then sometimes if I'm not focused I'll do 9K again with Kasumi or Phase automatically instead of doing a combo that I was hoping to do in the first place