Gotta say, what part of the welding do you mean specifically? Because here for example is the welding of a P3SL Cervelo (aluminium), which once upon a time was a top TT frame:
The welds on the Pinarello look maybe a tiny bit irregular in one or two spots, but it's not really that bad.
The welding CLEARLY shows that is a VERY LOW end frame - no "pro" (or even a keen amateur) would be seen dead on it.