Materail texture Problem

Hi All, I have some problem with the texture inside my material, i load al the texture (normal, specular ecc) and everithing it’s ok, after some minutes and also in play mode my texture goes down with resolution a lot, if i go inside my material and reload the texture evertything goes fine, but after some minutes resolution down again, thanks in advance, UE version 4.17.2

Maybe you have a low framerate and the engine puts the graphics automatically to low ?