According to your testing, does the issue occur with ONLY Immersive Portals mod installed?

Yes

Forge Version

40.2.0

ImmersivePortals Version

1.4.17-mc1.8.2

Latest Log

https://gist.github.com/Nox13last/8c88793cc19893c2c78f6d6785200c18

Crash Report (if applicable)

https://gist.github.com/Nox13last/ec2c216aba2ee9faf1d8b366912f222d

Steps to Reproduce

I have earmarked each step (as significant) with chat messages. These will be parenthetical. I figured you could use something to CTRL+F at each step.

1. Generate a new Creative World.
2. Pull the following items out of the Creative Inventory drawer: Obsidian, Fire Charge, Seed Analyzer.
3. (Optional) Build a Nether Portal. Standard configuration.
4. (Optional) Ignite the Nether Portal with a Fire Charge. (<Noxedwin> SPAWNING IMMERSIVE NETHER PORTAL)
5. Place a Seed Analyzer. (<Noxedwin> PLACING SEED ANALYZER)
6. Use the Seed Analyzer (<Noxedwin> USING SEED ANALYZER)
7. Watch.

What You Expected

For the Seed Analyzer UI to open. Also, for the Immersive Portal to continue to function.

What Happened Instead

The game explodes, performing an emergency world-save and then crashing to desktop.

Additional Details

I cannot confirm that this issue has not already been reported (#59), but as the OP had vanished last year, I am creating a fresh issue. I will crosspost them. Considering how well-written that issue ticket is written, I would honestly defer to it over this one.
The other element of this report is the presence of Agricraft. The version used here is 1.18.2-3.1.4. This is only two releases behind the final 1.18.2 release.

In the two tickets that I could find on Agricraft's GitHub, Immersive Portals is blamed specifically, with an imperative to report it here, and not there.

Please Read and Confirm The Following

• I have confirmed this bug can be replicated without the use of Optifine.
• I have confirmed the details provided in this report are concise as possible and does not contained vague information (ie. Versions are properly recorded, answers to questions are clear).
• I have confirmed this does not happen on the fabric version (If it does please report to here instead).
• I have confirmed I'm not using a hybrid server (Magma, Cauldron) or a different (non official) Forge Server release.
• I have confirmed this issue is unique and has not been reported already.

In cooperation with the referenced issue ticket, I would like to confirm that building a nether portal is unnecessary. Simply placing and using a Seed Analyzer is enough.
That issue ticket is really well-written - I can't do a better job myself. Shame the OP didn't come back to it.

In cooperation with the referenced issue ticket, I notice that the OP believes that the problem may lie in rendering a graphical object that IP is trying to get hold of.

With that said, there is an option in Agricraft's config to use GUIs instead of in-world animations. It does not help.

Crashy offers this, which is probably more of the same information.

Here is a comparison between the two modes. I will have to disable IP whenever I want to use this.

GUI Off:

GUI On:

In 'GUI Off' mode, the mouse-wheel rotates the helix to highlight each rung (base-pair). Maybe it's because my eyes need Unicode Font instead of Mojangles Font, but I think this sucks.