Locales/sort bug

[Rob Gom <rgom.debian@gmail.com>]

Hi all,
do you think it's a bug in either libc or coreutils (sort)?

$ cat test.csv
aph3,"APP",""
aph3_devel,"TXT",""
aph3,"MiB",""

$ LC_ALL=C sort test.csv # expected
aph3,"APP",""
aph3,"MiB",""
aph3_devel,"TXT",""

$ LC_ALL=pl_PL sort test.csv  # why is that?
aph3,"APP",""
aph3_devel,"TXT",""
aph3,"MiB",""

$ LC_ALL=pl_PL.UTF-8 sort test.csv # another unexpected output
aph3,"APP",""
aph3_devel,"TXT",""
aph3,"MiB",""

Could anyone give me a hint? I know that this is LC_COLLATE related
(LC_ALL as shorter version), but don't know whether it is my fault or
upstream bug.

I'd appreciate any comments.

Regards,
Robert