Flex edits misaligned after bounce in place

Hello, running LPX 10.8.1, after spending hours setting transient markers up in edit 'file' window then aligning flex edits to my track, I bounce in place & find that the audio region is badly misaligned. I have tried multiple methods of bouncing regions.

In the edit 'file' window is it possible to snap multiple transient markers to zero crossings at once? I've noticed on some youtube vids that this is a much needed feature. It's a proper pain doing it one at a time.

Any help will be much appreciated.