I just mentioned them in case there is similar issue with with their replacement.
Anyway, in Oblivion, most skills and attributes would have no increased effect if you buff them somehow over 100.
I always found that strange since maxing out a skill and then using an item in order to improve it even more never gave any benefit.
It also made lot of items nearly useless (Black Hand robes for example).
I really hope they fix this so we can continue to benefit from skills and attribute replacements when we max them out and then decide to buff them some more with magic/item/something.