Hmmm... for me it has always been that way that you need to boost your stat above 100 to being able to keep training... and I have never tried getting my skill above the 100 limit by natural means (I use no patches or mods nor have I Tribunal installed)

hhhmmm..nope, my Agility is 160 and yet I couldn't train my block more than 100.and yes, I have Tribunal too. and it's unpatched.