Mysterious latex problems?

I am working on a post with some latex equations. They look great and everything, but when there is a latex error of some kind it fails silently, and prevents changes from reflecting in my post.

Tracing down an error is a lot of work, but I isolated a few of them, and now that I've traced the problems, I am completely baffled. Very mundane things like adding () around something can cause it to fail, and I can't figure out why.

For example I have a line

$$A_{ij}$$ contains $$(X_{i,c}W_{c,0})X$$.

which apparently works fine because the page renders, but if I change it to

$$A_{ij}$$ contains $$(X_{i,c}W_{c,0})(X)$$.

then all changes I make to the document are blocked, and aren't reflected until I remove the surrounding () from X.

Another problematic snippet is

The resulting attention matrix is
$$
A = XW^Q W^K^\intercal X^\intercal
$$

Which renders the middle W^K correctly, but everything else is left as plain text..

Then if I include the subsequent paragraph, again, changes are blocked.

While this is easy to lay out, it is very difficult to interpret. The meaning of each barcode depends entirely on which other barcodes are present, so the meaning of $$W^Q$$ and $$W^K$$ can't be nailed down without context.

But if I remove it I can make changes again (but the proceeding equation still renders wrong)

I can't reproduce any of these issues with my own local latex environments, and I've tried all kinds of variations to figure out what is wrong.

Does anyone know what is going on?