parse error in Notebook

[papaworx]

In a notebook.rmd I have the prose:

Introduction {#sec-introduction}

Celebrating yet another birthday . . . .

On 'Save' I get:

Error in source("~/Documents/R/Projects/Brennan/Brennan_2.Rmd") :
~/Documents/R/Projects/Brennan/Brennan_2.Rmd:15:13: unexpected symbol
14:
15: Celebrating yet
^
Both 'Run' and 'Preview' operate correctly, although I have problems with \pagebreak not functioning.

[cderv]

@papaworx

source("~/Documents/R/Projects/Brennan/Brennan_2.Rmd")

A Rmd file should not be source()-ed.

How do you run this file ? What is exactly is the saving you do ?