Expected Behavior: If you go through a nether portal in spectator mode then it won't teleport you to the nether once you switch to survival, creative or adventure mode if you aren't touching a nether portal block

Observed Behavior: If you go through a nether portal in spectator mode then it will teleport you to the nether once you switch to survival, creative or adventure mode even if you aren't touching a nether portal block

The same also applies to end portals