Has anyone else encountered a problem with poster frames not recognising a video's pixel aspect ratio

I'm discovering a strange effect with some of the .mp4 videos I've upload into iBooks Author. They're Pal SD 4:3 .movs with a 16:9 pixel aspect ratio and they play out fine on the iPad. However the iBooks software seems to be ignoring the pixel aspect ratio of the poster frame. This leads to the situation.

1) When I drag my video into iBooks author all looks good - the video is 16:9 and if I choose to set a poster frame (or leave it at default) it looks 16:9 in the iBooks Author.

2) I preview my book and it opens in iBooks on the iPad. But now the poster frame aspect ratio is 4:3

3) I click on the video to start playing and it immediately jumps to 16:9 aspect ratio and plays out fine.

4) If it scroll down a couple of pages and then scroll back the video poster frame has now reset itself to 4:3

This sounds like a bug to me. Anyone else had it? Do you know if it's possible to report bugs without having a Developer licence?

Thanks for any help

Rob