No, It should not be an issue. Minimize/Maximize(normalize) does nothing special.
Only thing MC does when it gets focus again is to refresh file content, rescan the drive if needed.
and if the drives are in sleep mode or if it is network path that are shown, it can give an delay.
Also when a program is minimize Windows will allows the program to be moved to the page file, and when it is back windows will swap it back. that can also give an delay. (That should only happen if you run low on memory)