Comment 2 for bug 987199

I believe the problem may be that sharing a message does not necessarily update the date_changed on any affected POFiles. It's easy for POTMsgSet._setTranslation to decide to make a message active in other POFiles (in other release series or even between Ubuntu and upstream), but it's harder to figure out exactly which POFiles will see a change because of it.

And so, I suspect that we don't do that at all, failing to set POFile.date_changed, which is exactly what the translations-to-branch exporter looks at to decide whether the POFile needs a new export.

This might be fixable through some offline process, or perhaps the translations-to-branch exporter needs to look at more information than just POFile.date_changed.