Id love to provide you with some answers, but we use Plesk not cPanel at NetspaceOnline.net so can’t really offer you much support there.

I have had a similar issue once with Plesk however that appeared to be an issue at the client’s computer, some form of spy ware / adware infection which resulted in further issues with him accessing his hosting account. The problem was quickly resolved after informing the client he could have spy ware infections and that a regular spy ware scans could prevent any further issues.

I do hope some of the members here who do use cPanel are able to provide you with some feedback. Keep us posted as to whether this happens again