I have encountered a strange issue which only happens on servers.
I run a SpongeForge server of a my own modpack (160 mods) on 1.12.2 with Nucleus installed. My apologies if this is not the right place to ask/report this.

Whenever I try to use /home that needs to teleport me cross-dimensional, I get an error. (Like: From Overworld to Nether, from Nether to Overworld, from Nether to End.)

Errors I get ingame:
Without Nucleus: https://pastebin.com/TCf8VSmf
"Error occurred while executing command: java.lang.NullPointerException."
With Nucleus: https://pastebin.com/0EZKKi9a
"Unexpected error running this command: null"

Debug.log with Nucleus: https://pastebin.com/gxFUx9KX

I've tried different versions of SpongeForge and with and without Nucleus. The bug only goes away when removing BetterPortals from the server mods folder, so I am asuming it is BetterPortals (partially) causing the bug.

I've added the error from the console. One with Nucleus and one without.

I hope you, or someone else, can help me fix this or point me in the right direction if this is not the place to ask this.

Not directly related but probably good to know: Do BP portals themselves work as expected?

This is likely caused by a conflict with some third-party mod (or an update to SpongeForge).

Could you test spongeforge-1.12.2-2838-7.1.7-RC3910 with your modpack? That's the lastest version of SpongeForge which I've tested BP with.

Please also attach the full debug.log file, you seem to have accidentally copied the wrong thing, two of the pastebins have the same content.

BP portals do work as expected, I also really like the mod so that's why I am looking for a fix to prevent having to remove it from my modpack to get portals and teleport commands to work again.

I've tried it again with Spongeforge 7.1.7-RC3910 but I am experiencing the same issue.
Here are the debug.log and latest.log of the server. (I quit the server right after attempting the /home command so it happens near the bottom.)
latest.log
debug.log

I just noticed that Aroma1997's Miningworld portal is not working at all on the server. Singleplayer is working fine, just like the /home issue.