Not quite, the First Ukrainian Front designation did not mean the troops were recruited in Ukraine, it means that at some point all the fronts were reorganised and redesignated according to where they were located along the entire frontline, and kept their designation henceforward, even long after leaving their departure point (North Ukraine in this case).

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Everly Brothers - What I Have To Do Is Dream
"Never wrestle with pigs, you both end up getting dirty and the pig likes it."