Premiere Rush Export error - Flashing images, image going negative with green/pink lines

Hello, can anyone help? Over the past two weeks, my Premiere Rush has been messing up exports massively. It looks fine in the programme and seems the issue occurs when exporting. The image flashes, it has green and pink lines overlayed on the video, it goes negative to normal. A total sh!t show tbh. The issue seems to stop after about 12 minutes of a 1h 10-minute video.  I thought it may be due to the original files being on a hard drive, but I have now put them onto the computer and it's still happening. Please see attached images. 

I'm using Premiere Rush 1.5.34 on a MacBook Air (macOS Big Sur version 11.0.1 - 20B29) - 

Processor - 1.3 GHz Dual-Core Intel Core i5

Memory -  8 GB 1600 MHz DDR3

Graphics - Intel HD Graphics 5000 1536 MB

It has been totally fine until about two weeks ago. I have tried a few fixes I found online, like preparing the video for playback then exporting and trying different export settings. It has been doing it on all my recent videos. 

Has anyone else had this issue or know how to fix it? I'm paying for this and cant export anything!

Thanks so much.

Saffi