Untracked files cache not used when --untracked-files is used

I am using: git version 2.51.0.windows.1

Run: time git status --untracked-files

I get: It took 2.75 seconds to enumerate untracked files, but the results were cached, and subsequent runs may be faster. See 'git help status' for information on how to improve this.

real 0m2.959s user 0m0.000s sys 0m0.000s

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when I run it again, I get the same thing again

However, when I run it again WITHOUT --untracked-files its much faster now: real 0m0.753s user 0m0.000s sys 0m0.015s

which means that the untracked cache does work (bc deleting the untracked cache, it will be slow and also show the message) per the docs:

Which I can confirm also with: git update-index --test-untracked-cache

It seems that using --untracked-files(=all) causes it to either not use the untracked files cache (or untracked files are not stored in the untracked files cache if they are in an untracked directory?) Since various tools and IDEs use that hardcoded, fixing this would be a massive performance boost for many users