As the title says, all level 70 recipes require t8 materials, this renders all lvl 70 combat arts and spells uncraftable until the release of kunark.
Not a bug it's the way it works. All level x0 recipes get upgraded to the new expansion's materials which causes this problem on TLE. It's going to happen again at level 80. And I can't see them changing it as they'd have to change it back again when the materials go in.
I'm not here to argue and fail to see how that comment helps the situation further. This is where customer service sent me after explaining to me that it is a bug and is likely an oversight. I cant imagine that it was planned to not be able to make 3 or 4 spells per class as experts.
CS did you no favors then. It's neither a bug, nor an oversight. It's something we've been complaining about for 5 years now to no effect. We were told pretty much from day one of TLE when we couldn't craft level 50 spells that this was our reality.