Can't speak to his point, but Ti is more prone to notch failure than other materials (depending on the alloy, temper and depth of notch). But this scratch's orientation is favorable compared to one running along the weld line.

Either way, it barely matters because there's not anything the OP can do about propagation or potential notch failure. What will happen will happen, if it'll happen, but it could be years out so the OP can cross that bridge if/when he comes to it.