Sound not synced after rendering

Hi Guys

I have a little issue.

A couple of my videos recently have shown sound and voice syncing problems after render.

There seems to be no issue during editing but when I watch the video after rendering the last half of the video shows some sound sync issues. It's very visable during any talking.

Maybe out  by half a second.

I am using a gopro hero 5, Huawei Mate 20x and DJI spark for video.

I mention this as it doesn't matter where the video/ audio comes from, the syncing issues always comes out. Check this video https://youtu.be/tP0wIpnirI0 syncing issues comes at about 6 minutes

I have tried updating Rush, uninstalling and cleaning out my laptop. Laptop is reasonably high end and should be able to handle it all fine. SSD, 16GB ram. AMD Ryzen 7 3700U with Radeon Vega Mobile Gfx 2.30 GHz.

I am starting to lose interest in Rush and simply want it to work.

I have also found with the latest update that any downloaded transitions, titles and MGRTS do not come up in the list. I am stuck with the stock transitions etc.