bootcamp partition issue in High Sierra

Hi

I'm doing my first BootCamp install in High Sierra

(i've done 9-10 in other MAC machines)

read the manual

watched a couple of youtube video's

i'm stalled at the point where, when Windows setup is running

it has passed the point of my license key

asks which partition

and says it can't install on the bootcamp partition

(says it has to be NTFS)

i back out

boot back up in macOS and run disk utility and disk utility says it is in fact NTFS

did i zone out somewhere where there was a secret handshake or something i missed?

thoughts, idea's comments?

thank you

rr