If on a Server (not singleplayer, a real server!), the client will crash with bonsai trees & immersive portals.
How? When having a bonsai pot in your base and setting up a portal (to the nether), you go trough the nether portal and go exploring. When returning to the portal the client crashed as soon as you get close (rendering distance?) enough. The client will keep crashing as soon as he tries to reconnect to the server. Making it imposseble to connect.

I reported this also to iPortalTeam/ImmersivePortalsMod#133