Integrated learnr tutorial STILL not opening on Desktop

This topic was closed, but I am still having the same problems as the original poster in this topic:

I have everything updated:

R version 4.0.2 (2020-06-22) -- "Taking Off Again"
Copyright (C) 2020 The R Foundation for Statistical Computing
Platform: x86_64-apple-darwin17.0 (64-bit)

Version 1.3.1093

> packageVersion("rstudioapi")
[1] ‘0.13’

Here's the error message in the Jobs pane:

Error: lexical error: invalid char in json text.
          ":"character","attributes":{}<!--html_preserve--> {"type":"l
                     (right here) ------^
Execution halted