Failure on markdown table

[Bisaloo]

Reprex-ish:

---
title: "Test: Table"
output: html_document
---

| col 1 | col 2 | col 3 | col 4 |
|:---------------|:-----------|:--------|:----------|
| Brightness     | Total brightness, total reflectance, spectral intensity | test | test |

fails with

Error in x[["class"]] : subscript out of bounds

But if I try to change a single thing from this example, it works... I'm not sure what's happening.

It works fine when used with rmarkdown::render()