You have Bermudagrass in Zone 5 ???

Unfortunately, I do :(

Okay, if you say so...

I've used Sethoxydim on KBG (for Stiltgrass). I would strongly suggest a test patch first before applying it widely. I experienced (temporary) stunting of the KBG, but that type of behavior can vary cultivar to cultivar.

Thanks. I have a couple big patches that have been spreading for the last 2 years and even came back after applying Roundup :( Hopefully this'll kill them for good and won't mess up my lawn :)

IIRC, the Roundup is only going to kill the top growth. You have to keep after common Bermuda as it spreads via stolons & Rhizomes. One round of RoundUp isn't going to do it.