I stumbled upon this thread after having a similar issue with reveals on my elevations, the lineweight was simply too thick. As others have pointed out, it's due to the reveal cuts creating new edges on the walls.
The solution I found for our use, which I suspect does not resolve the main issue, is that there was a graphic override on the wall silhouettes. (VG Overrides > Model Display > Silhouette drop down menu) For some reason our View Template was using a thicker line weight for the silhouette and that was affecting the reveal "cut" line weight. Setting it to <none> should use the thinnest line weight for your elevation.
If you still care about having a silhouette on your walls: don't bother overriding the wall projection lines in your template, the same override will affect the areas with reveals. Instead, use the "Linework" tool to individually override the edges of your walls instead of letting Revit do it for you since it goes overboard and applies that silhouette rule to reveals. Even if it's tedious it's much easier than going around and overriding all the cuts made by reveals especially if there are a high number of them.
Again, not resolving the core issue by OP but this is the workaround I found.
