Rendering with H.264 causing audio video sync issues on Mac products

I'm baffled but if you want some help digging in to this, I'm willing to give it a shot.  Since I work on both macs and windows machines (and an adroid phone) if you want to post a link to a sample, happy to take a look and listen.  In the meantime, wondering if there's something odd in the sampling rate of your h264 files.  Couldn't hurt if you could tell us your source properties, sequence settings and export settings.  And if not, could you try using one of the youtube presets and see if the results are the same..  And although I don't know if you could be making a difference, please tell us your system specs: OS version, Premiere version, amount of RAM, Hardware specs including graphics card.   It's snowhing in NYC and I have to finish my taxes, so looking for an excuse not to...

Thanks,  but no I'm not using variable frame rates.  I have used Handbrake in the past when filming with my phone but that is not the case in this instance. 

Thanks again for taking the time for your input. 

are your sources all constant frame rate?  If not, variable frame rate may be the source of the issue

use mediainfo to determine whether your source is variable or constant frame rate

https://mediaarea.net/en/MediaInfo/Download

if it's variable use handbrake to convert to constant frame rate

https://handbrake.fr
and here's a tutorial on how to use handbrake

https://www.youtube.com/watch?time_continue=34&v=xlvxgVREX-Y