Invalid character in R

Question

I turn the [ ] character into an A letter, within a R data.frame. It works perfectly, though, when I create a ". bat" to run this algorithm automatically by windows tasks it displays the following error in R out log file:

API$tabela<- str_replace_all(API$tabela, "[
API$tabela<- str_replace_all(API$tabela, "[?]"
Execution halted

Below is my ". bat":

ECHO ********************************************************************
REM ECHO com diretorio selecionado iniciamos  o script
ECHO ********************************************************************

"E:\Softwares\R-3.6.1\bin\x64\R.exe" CMD BATCH --encoding=UTF-8 E:\arquivo.R

ECHO **************************************************
REM ECHO pausar e verificar o estado final
ECHO concluida
ECHO **************************************************
pause