With proxy mode enabled, re-adding a media clip to the project playlist that was removed from it will create a new proxy for that clip. The “new” source clip (proxy of a proxy) does not have the name of the original video but that of the hashtag of its first proxy. Its own hashtag is a new one, different from the hashtag that is its source clip name. I haven’t tried exporting to see if the new proxy will be replace with the original full-rez clip or with the first proxy instead.
Windows 8.1 (64 bit)