[Xfce-i18n] Transifex bug in xfce4-power-manager PO file?

[Pjotr]

Apparently there's a bug in the current Dutch translation file of
xfce4-power-manager in Master:
https://translations.xfce.org/projects/p/xfce/r/master/l/nl/

Whenever I try to upload the corrected fuzzy translations of the last
remaining strings of xfce4-power-manager, I receive the following
error message:

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Hello Pjotr, this is Transifex at http://translations.xfce.org.

Our system detected a failed file submission (po/nl.po) to
xfce4-power-manager | master. In order to avoid losing any of your
work, you may find the files in question attached to this e-mail.

This error was triggered by a failed correctness check (msgfmt -c) on
the file. The error was the following:

po/nl.po:485: message catalog has plural form translations...
po/nl.po:3: ...but header entry lacks a "plural=EXPRESSION" attribute
          Try using the following, valid for Dutch:
          "Plural-Forms: nplurals=2; plural=(n != 1);\n"
po/nl.po:3: ...but header entry lacks a "nplurals=INTEGER" attribute
          Try using the following, valid for Dutch:
          "Plural-Forms: nplurals=2; plural=(n != 1);\n"
msgfmt: found 2 fatal errors

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This happens every time, both when I use the web interface and when I
upload a manually edited PO file.