PNGs losing transparency

I frequently use PNGs With transparent backgrounds when editing photos on my phone and lately I’ve been having a lot of problems with them.

Maybe a third of the time, I’ll save a PNG and have no problems, but a vast majority of the time, I’ll save a PNG and when I import it to a photo editing app it suddenly has a white background.

What’s more, when I try and import that same PNG with a white background into an eraser app to manually erase the background... ITS TRANSPARENT AGAIN!! *** IS GOING ON?!?!

I seriously feel like I’m losing my mind. I have PNGs that are only transparent when I need them not to be and I have no idea what the problem is.

I have the ‘Optimize iPhone Storage’ setting turned off so I know that can’t be the issue. I’ve also made sure that the files are actually saving as PNGs and I know that’s the case. I am seriously at the end of my rope.

Any insight would be greatly appreciated.