Default [Q] Line test performs some sort of recalibration?

About three days ago, my One suddenly developed the (apparently typical) dead band on the digitizer about 1/4 from the top, stretching all the way across the display. Spent the next day or so removing apps, flashing ROMs/RUUs to no avail.

I then went into the diagnostic tools and ran the line test, after which the problem has completely disappeared.

Question is... does the line test recalibrate the digitizer in some way, or was this just a complete coincidence? Also, is the issue likely to reappear sometime soon?