Lean to ignore it?
It is completely irrelevant for the quality of the PCB.
Remember that when you’re designing a PCB, you’re often looking at a 20x or more magnification, and the end result will be half hidden under the soldermask anyway.
Change of track width is also slightly problematic with KiCad, as the change is an “unmovable point” during dragging.
What is your intention of this (very minimal) track width?
Is it needed to get to pads without clearance issues?
If so, then why not simply keep the thinner track? The difference is quite minimal.
And what are your actual track widths? Are they based on current handling or on PCB manufacturer capabilities or “other”?
If you stack a bunch of such cosmetic preferences on top of each other you can get a serious time waster without even realizing it. It takes some effort to “unlearn” such preferences, but it will improve productivity.
Learn to ignore it?
It is completely irrelevant for the quality of the PCB.
This is primarily for flex circuits, where the mismatch creates a stress riser resulting in a broken trace.
Change of track width is also slightly problematic with KiCad, as the change is an “unmovable point” during dragging.
This is actually a larger issue than the cosmetic appearance. I hope the new rule-based areas will allow tracks with different widths to accommodate this at some point, as with rooms in the Altium interactive router. I’ve haven’t worked enough with the new Kicad rule-based areas to see if this is the case or even if this is on the wishlist.
What is your intention of this (very minimal) track width?
This was just an example I put together. A more realistic example might be a long power trace with a width of something like .030" that has to neck down to .006" for clearance reasons.