Video speed jumps/choppy after Rendering

I have been using Premiere Rush for over a year with very little issue. 

I am using a S10+ and have Android 10. 

The issue I have is when I am in the editing stage the video playback is great as it plays through the clip.

Now when I try and render and its saved to my gallery, the saved gallery version playback after half way through is laggy/glitchy .

I have uninstalled Rush and reinstalled and even tried removing transitions and changing length of time on certain clips. Nothing is working. 

Any help?