Thibault IV «le Grand»  de Champagne, comte de Blois - Parents which set correct?

You are absolutely right. That profile is well documented with reference to Medlands.
Terry Anne Jackson, curator for Thibault IV will certainly correct the mistake.

@Terry Anne Jackson, this is an issue that I think you should look to. You being the curator I did not want to correct the master profile note.

This Thibault of Champagne is the son of Stephen of Blois and Adela of Normandy. Look at his dates; they're that of Stephen and Adela's son.

Thibault 1V is the son of Stephen of Blois @ Adela of Normandy

I do not mean to be picky - but there are some and especially newbies to genealogy who would take what the curator wrote as being the accurate and true data over what tree and the evidence and documentation says and since it has been written.... it just takes one person....