MusicXML tag <forward> interpreted incorrectly

It appears that the MusicXML tag <forward> is interpreted incorrectly by Musescore. In the attached file an invisible 1/8 rest in measure 2, beat 1 is encoded as follows (lines 111-114)
<forward>
<duration>1</duration>
</forward>
Musescore doesn't translate this into an invisible rest causing a measure which appears one 1/8th beat too short.
System info: OpenSUSE 12.1, Qt Version 4.7.4, MuseScore: Music Score Editor; Version 1.1; Build 4611

Thanks
gb7