Oil delivery systems changed in the Testa's the overcome this problem.
But I guess it's a bit early to tell yet.
Problem arose around '96 when the plating started to be outsourced instead of managed inhouse (Texas Pacific takeover.....). It's persisted until the re-design of the engine into the Testastretta.
MarioP has had a rocker snap in a Testa engine. But that's a non standard build with special parts, and is being examined and repaired by Ducati Special Projects, so is probably not indicative of a general rocker problem.
[Edited on 1-7-2005 by Mr_S]