Loading Levels in VR - Fade To White strange lines in HMD

Hello everyone! Hope I could find help here.
I am trying to load a new level with a fade to white transition but when the next level is loaded the screen freezes for a second and weird black square/lines appear frozen when moving my head.
P.S. If the screen fades to black the lines are not visible since they are also black.
Any ideas?
Thank you!