Although I don't (yet) have an Emisar in Ti, I have had many different titanium flashlights, both custom and production.
Although there are exceptions, generally the threads on the customs are rather smoother than those compared with the mass production items, and usually substantially so.
The issue is that Ti is prone to galling, and any minor imperfections (variances, tolerances, etc) in the threading will tend to "grab"
Appropriate lubrication will help, sometimes quite a bit, and normal wear does tend to "break in" the threads (at the expense of microscopic material loss, associated thread wear, and in extreme cases thread sloppiness)
I think that is mostly what discolors the lubricants as they darken ... more metal particles than actual "dirt" in many cases.
In any case, I find that the Krytox tends to darken more slowly after the first few changes :shrug:
