Bibtex to csljson conversion loses mathmode markers

[hseg]

Explain the problem.

With the following bibtex file:

@MISC {3252037,
    TITLE = {Isomorphism between projective varieties $\mathbf{P}^{1}$ and a conic in $\mathbf{P}^{2}$},
    AUTHOR = {Viktor Vaughn (https://math.stackexchange.com/users/22912/viktor-vaughn)},
    HOWPUBLISHED = {Mathematics Stack Exchange},
    NOTE = {URL:https://math.stackexchange.com/q/3252037 (version: 2019-06-05)},
    EPRINT = {https://math.stackexchange.com/q/3252037},
    URL = {https://math.stackexchange.com/q/3252037}
}

running pandoc -f bibtex -t csljson produces

[
  {
    "URL": "https://math.stackexchange.com/q/3252037",
    "author": [
      {
        "family": "(https://math.stackexchange.com/users/22912/viktor-vaughn)",
        "given": "Viktor Vaughn"
      }
    ],
    "id": "3252037",
    "note": "URL:https://math.stackexchange.com/q/3252037 (version: 2019-06-05)",
    "publisher": "Mathematics Stack Exchange",
    "title": "Isomorphism between projective varieties \\mathbf{P}^{1} and a conic in \\mathbf{P}^{2}",
    "type": ""
  }
]

In particular, note the math mode markers in the title are dropped.

Not having noticed this, when I then ran yq -y . - and pasted the result in the references metadata key, I got very confusing errors regarding missing mathmode markers.

Pandoc version?
3.1.12.3, commit 6ee0384, on Arch Linux