Why does a newline in PS1 throw a syntax error in Git for Windows bash?

I am trying to set my user prompt in the Git for Windows Bash prompt. Here's a (very simple) prompt that works:

# \@                 Prints the time: 11:14 AM
# \w                 Prints the full cwd path
# $(__git_ps1 ...)   Prints the current git branch

PS1='\n[\@] \w $(__git_ps1 "(%s)") \$ '

As soon as I add a second newline character into the mix, I get the following error:

 bash: command substitution: line 1: syntax error near unexpected token ')'
 bash: command substitution: line 1: `__git_ps1 "(%s)")'

The variant of the prompt that throws this error is (note the newline before the $ prompt):

PS1='\n[\@] \w $(__git_ps1 "(%s)") \n\$ '

I'm thinking there must be an issue with the __git_ps1 routine that's causing this issue to occur, but I don't really understand it. Is there something simple here that I'm missing?