Is caching not working as expected?

[IndrajeetPatil]

I was expecting that the second call here would be faster because it would use cache, but that's not what I see (at least locally).

library(lintr)

local_dir <- "/Users/indrajeetpatil/Documents/GitHub/lintr/R"

# the same behaviour is also seen with `lint_package()`
lint_dir(local_dir, cache = TRUE)
lint_dir(local_dir)                # I'd have expected this to be quick 

Either I am doing something wrong, or the caching is not working as expected.