Does Time Machine change file permissions while doing a backup?
This site is devoted to answering questions about Apple Products, but it's aimed more towards comsumers than power users. That doesen't mean your question is "wrong" in any way or you should remove it, but I strongly reccomend to ask it at the Super User Stackexchange site, which is devoted to power users like you. I think you might find there someone who can answer your question much sooner than here.