Particles get rendered behind the nether portals wich makes it look like they are behind it wich is not correct
I've tested this with multple particles they all have the same issue.
Environment
Windows 10
Intel(R) Core(TM) i7-3770T CU | 2.50GHz Quad-Core
16 GB DDR3
NVIDIA GeForce GTX1080
Java edition
Release 1.14.3
I Don't think its due to my specs 😉
Duplicate of MC-9553.