JGit TreeFilters behaving unexpectedly - jgit

Question

I have been trying to use JGits's TreeFilters to obtain all files with a specific suffix except for one specific file. However, the filters do not work as I would expect. Can someone please explain? (I know that implementing my own TreeFilter as a workaround is easy.)
PathSuffixFilter.create(".xml");
Result (as expected): All files with suffix .xml.
PathFilter.create("dir/sub-dir/pom.xml")
Result (as expected): dir/sub-dir/pom.xml
PathFilter.create("dir/sub-dir/pom.xml").negate()
Result (as expected): All files except dir/sub-dir/pom.xml
So I combined these filters with AndTreeFilter in order to obtain my desired result:
AndTreeFilter.create(
PathSuffixFilter.create(".xml"),
PathFilter.create("dir/sub-dir/pom.xml").negate()
);
Expected result: All files with suffix .xml except dir/sub-dir/pom.xml
Actual result: All files with suffix .xml that are not in dir.
So I further investigated:
AndTreeFilter.create(
PathSuffixFilter.create(".xml"),
PathFilter.create("dir/sub-dir/pom.xml")
);
Result (as expected): dir/sub-dir/pom.xml
AndTreeFilter.create(
PathSuffixFilter.create(".xml"),
PathFilter.create("dir/sub-dir/NOT_EXISTING.xml")
);
Result (as expected): Empty
AndTreeFilter.create(
PathSuffixFilter.create(".xml"),
PathFilter.create("dir/sub-dir/NOT_EXISTING.xml").negate()
);
Expected result: All files with suffix .xml
Actual result: All files with suffix .xml that are not in dir.
AndTreeFilter.create(
PathSuffixFilter.create(".xml"),
PathFilter.create("NOT_EXISTING/sub-dir/pom.xml").negate()
);
Result (as expected): All files with suffix .xml.