When You Enter A Nether Portal You Sometimes Suffocate In Its Walls

I was on my realm when I entered a nether portal from the nether side to the overworld and suffocated in the portals blocks. This also happened again but I was going from the overworld to the nether and I suffocated in the portals blocks.

 

-I don't know if this is realms exclusive but I have not experienced this problem elsewhere.