Dear frame building experts,

Hopefully this is the right section of the forum to ask. If not - let me know!

I just got this Tempest titanium frame that I am about to build up. The welding looks well done all together, but to my surprise I found discoloration on the inside of the head tube at the down tube joint.

Can anyone with good knowledge in bike frame titanium welding tell me if this is something to worry about? The surface is slightly rugged at the discoloration.