lost over 1000 stone and almost all progress on building

we have had a problem recently when the server restarts your current progress goes to your compound rather than the building you are working on. Any chance this would be the case for you?

It didn't show up on the compound in the city I was working on, but it may (possibly) have shown up on a different city compound. I don't think we had stone added on the one at aimne and we do now.