Are the .fpj files of your project writable? Do you use any form of source control?
From what I'm seeing my own guess here is that RoboHelp is still believing that the content belongs to word.
I might suggest the following steps.
Open Winows Explorer and make copies of the HTML files involved. Then from RoboHelp, delete or remove the content. Then use the Import function to add the desired HTML files back into the project into the desired folder.
My thought is that by taking these steps you will have effectively disassociated Word and the topics should now be independent topics that RoboHelp should allow you to manage as you wish.
Hope you get it sorted... Rick
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Yes, all my files are writeable. No Source Control. I ended up doing a cold boot on my machine and, low and behold, it was back to normal. I had even done a restart before that and it didn't fix the problem. Got to try the easy stuff first! Thanks for your responses and help. Always much appreciated!