I have logic to change material based on spline ID in one circumstance, and based on a parameter in the object in another.
Let's say if Spline Mat ID is 2. I then change Mat ID 1 to Mat ID 2 using a Material node.
Later on if I change Mat ID 1 to Mat ID 3 if a profile variable is enabled, it will change those faces I already changed earlier.
(I will for now work around this by changing the order of these changes and changing the spline mat id things after the profile variable - but I would not expect it to overwrite what I already did and this is not always possible)