Please Help!!! Weird Textures after packaging project

Hi Everyone!

I’m having a weird issue with some textures on a level I’m currently working on using Unreal Engine 4.11, all of them were made on Substance Designer, the thing is, on the editor it runs flawless

Even the stats, if I understood correctly all the profiling stuff, are good, but once the project is packed, it takes AGES to open, and some of the textures are lost

This happens randomly, not always with the same texture, and it changes with every package I do for testing.
Please help, I really need this problem fixed quickly.

Thank you!!!