Thanks Lomo. Definitely more shims seem needed at least. However, even if they use pressure treated shims, I am afraid that they can still rot or be damaged by termites. I understand plastic shims won’t, but I am wondering if there is more proper way to fix the gap.

I used to always see steel shims used, plastic would fine as well.

Talk to your general contractor then educate us.

More pictures would be more informative.

When blocklayers on one of my builds failed to level the courses, the framers used wood shims. Later, my engineer said steel would have been the preferred fix.

The bigger question to me is what type of wood they used on the sill plate. That looks like pretty poor quality, particularly for use as a sill plate. Is it pressure treated? It looks like thinner pieces of wood, as opposed to a 2x6. Maybe the picture is deceiving.

TT that is a 2x6. yellow pine and the rim joist above is quite large throwing off the scale. Pic being 3 inches away does not help, lol.

Looks like a vapor barrier is used instead of pressure treated lumber. If so, move the shims above the vapor barrier for rot protection.