What does --remap-path-prefix in non-cacheable reasons mean?

[emilyyyylime]

I'm trying to use sccache to improve build times of packages installed using my package manager of choice (paru, AUR). I've set sccache as my rustc wrapper but I'm not noticing any improvements apparently because crates are being built with those arguments. Is there no way to configure sccache such that subsequent builds of packages don't have to rebuild all dependancies?