If a .pro file is used that contains SUBDIRS or if multiple .pro files are included on the commandline and .ts files exist that have been translated only the first .pro processed will keep the status of its existing translations, all subsequent .pro files will have their associated translations set back to 'type="unfinished"'. On some occasions the valid translation is removed too.

In the attached set of excerpts from .ts files generated on the same code you can see how type="unfinished" is added to different translations depending on the commandline of lupdate. I've tried this using the lupdate from Qt 4.4.1, Qt 4.6.0 and Qt 4.6.1