I'm having the same issue as the original poster, but probably for a different reason.
I have images taken with 2 different cameras (HP 315 and Finepix S5000). Images from both show the proper flash state (fired or not fired) with the original exif data intact when uploaded to PP.
However, when I edit the properties on the image to add in the author and some comments regarding copyright information (right-click--Properties--edit fields--click Apply, then OK) and then upload them, all of the images show the flash state as "fired", whether it really was or not.
In looking at exif.php, there are 2 cases in the code, onefor MakerNote (I presume author) and one for UserComments. The code is as follows:
case "927c": $tag = "MakerNote";break; //a bunch of data
case "9286": $tag = "UserComment";break; //text string
There is nothing in the rest of the exif.php code to process that information, as I cannot find any lines with those tags in them. I'm not a programmer, and have no clue how to go through exif.php to fix this.
I know that this is not a Pixelpost program issue, as exifer 1.5 is an external process include within PP, so I am not expecting any of the devs to address this issue.
I did, however, want to bring it to everyone's attention as a possible cause for this problem, in case anyone else was having it and wondering why.