Images look blurry when previewed or published Captivate 9

Similar to another thread but as it is so old perhaps I should start a new thread.  Sorry for the duplication.

I have built several drag and drop interactions.  They use a cast of characters 276x604 at 72dpi saved as .png files with alpha.  now I can put 4 characters in a line-up, reduce their size to approx. 50% and on screen (1280x720 stage) all looks fine.  Preview just that slide/interaction and all looks fine.  Preview the whole project or publish it and 1 of my 4 characters looks blurry??  They are all the same size, all came from the same source .ai file with certain layers turned on or off to create the different characters.  And just this 1 character blurs???  I've tried re-sizing in Captivate, resaving in PS, moving on stage in CP.  Nada.  Again, preview just the slide they are on and it looks perfect, only when I preview the whole project or publish it does it go blurry.

I tried something else.  I reduced the size of the .png character by 1 pixel horizontally in PS.  Now that fixed the problem on the slide in question but is now giving me issues and moved the problem to another slide where the character was smaller...

Seems like a bug.  The image itself is only 25K, flat colours and saved as .png in the "no compression/no interlacing" settings the same as the other characters that look fine.