Unwanted sanitizing (escaping) in knitr due to update - r

Question

Last Spring, I used code similar to my minimum working example (MWE) below to make this: https://cdn.advocacy.sba.gov/wp-content/uploads/2019/04/23142650/2019-Small-Business-Profiles-MA.pdf
According to the knitr documentation, the table code should not get sanitized. If you knit the MWE however, you will see that several characters do get sanitized (escaped). For example, \ is sometimes turned into \textbackslash{}. So, it seems that some package update has changed when code gets sanitized. If you simply copy the RMD table code from below and paste it into the TeX output, it compiles fine.
I have tried reverting back to many of last year's packages, yet to no avail.
---
title: "MWE"
output:
pdf_document:
keep_tex: yes
---
\begin{tabular}{#{}lll}
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
&
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
&
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
\end{tabular}
*[In my original code it was part of an "asis" chunk. You can try this, and find the same problem.]

Answer 1

This is a known problem and the solution is to add raw attributes to pandoc, which ensures that content inside the block is not escaped.
1) Add md_extensions: +raw_attribute
2) Add a latex block
For your examples this works as follows:
---
title: "MWE"
output:
pdf_document:
md_extensions: +raw_attribute
keep_tex: yes
---
```{=latex}
\begin{tabular}{#{}lll}
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
&
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
&
\begin{tabular}{ll}
A & B \\
A & B \\
\end{tabular}
\end{tabular}
```
or when using it inside a code chunk:
```{r, results = "asis"}
cat("```{=latex}")
// your latex code
cat("```")
```
P.S.: pandoc version 2.0.0 is needed for this feature