Basically what the title says.

I activate my texture packs, and they stay for as long as I’m in the app. But once I fully close the app and enter again, it is reset to the default textures and I have to re-activate my texture packs.

Video below demonstrates better, had to use drive because the file size was bigger than the site allows

https://drive.google.com/file/d/1yzdKyIZ949WzYDLUnyanm7M_M4X2Nf6r/view?usp=sharing