Weird INDENT formatting in some previews - never happened before

Hello -

has anyone had problems with weird indents recently?

I never had problems before, just used paragraph-indent in Open-office or Word setting indents for the whole document as recommended in all guides.
With a new novella I'm trying to publish these days I see that indents come out OK in the Kindle Fire and Kindle HD web previews on the KDP website, but they are all gone in all the other previews (old Kindle, ipad, i-phone...)  Strangely enough if I don't indent paragraphs, I get indents in this second category of devices and no indents in the first one.  
It seems this is not just my problem. I saw a couple of other recent posts on the Kindle Community forum by folks experiencing exactly the same.
To add more to the mystery, if I run the file through KindleGen on my Mac and check the .mobi on Kindle Previewer, everything looks fine.

Anyone having the same problem? Can this be just something created by the web interface and the books look all right on the physical devices? Suggestions?  

Thanks!