I am having a similar problem when updating new Sharepoint pages. I have been adding multiple segments on the page. Each segment contains a Text webpart and a divider. I have been copying and pasting text and inserting pictures or charts withing the text webparts. The datasource is Word documents. There are no formatting issues. Randomly, I can not determine a pattern as of yet, when I click into a new text webpart or sometimes when I'm publishing the page, all of the other data in the text webparts on that page are cleared. The only remaing data is the most recent segment. The text webparts and divider are still there, but all of the words, pictures and charts are gone. If I catch it immediately, I can hit the back arrow and it will replace the text data in all of the segments. More often than not, I'm too far down on the page to see the previous segments lose their data until it is too late.
As a workaround I am currently having to perform dual maintenance on 2 pages so that when the data is deleted from the page, I can recreate it by copying and pasting it back into all of the blank text webparts from the second page. It does not appear to be happening to pre existing pages during updates. I started noticing the problem on new pages created last week. I have checked revision history and sometimes I can find the lost data there, but sometimes it is lost during republishing. While I have created this time consuming workaround, my fear is that when someone else performs a future routine update on the page, all of the data will be lost because they won't realize they need to perform dual maintenance to the whole page.
Are there any scheduled bug fixes for this problem?