Crash Log

Said item frame was attached to an oak planks block.

Nope. A generic planks block.

Oh, interesting. Unfortunately I'm unable to reproduce the issue.
Could you try this build and see if it fixes it for you? https://jenkins.girafi.dk/job/Passthrough%20Signs/job/Passthrough%20Signs%201.14.4/7/

I’ll test when I get back to my computer later tonight (or possibly tomorrow if something comes up).

I just noticed the list of ASM transformers after each line, so I’ll test with those removed to see if one of them is breaking things.

It might be. Could you take a screenshot of the placement of the item frame that causes the crash?
I just noticed that it's actually crashing on a Stairs block, so maybe some mod that's making stairs into chairs.
I can probably fix it on my end, just need to be able to reproduce it first.

Thanks for your report!
Do you mean a vanilla chest, or a oak chest from Quark?

Glad to hear that the Jenkins build fixed the issue!
I'll release a new build on CurseForge in a bit.

I can't sit in stairs in this pack, so that's out of the question.

I just tried removing and replacing the item frame, and it crashed with the same error.

The testing version seems to fix the crash, and it still works as expected.