So I recently switched to a Samsung Galaxy A50 with One UI version 1.1 build over Android Version 9.
So, I've been facing an issue with thumbnails regeneration. The DCIM/.thumbnails folder keeps deleting its content next day (which I suppose is a feature to save memory). But, the problem occurs when the contents aren't able to regenerate themselves. The gallery apps itslef is working fine and regenerating thumbs properly but not creating new thumbs in the DCIM/.thumbnails folder due to which I'm unable to post on Instagram and Reddit.
I tried clear data and clear cache on gallery, rebooted my device but it,s still no good.