str_remove: dealing with punctuation

Question

Using the following code works to remove everything left of "E":

library(stringr)
x<-("ABC DEF?")  
str_remove(x, "ABC D")

However, the following code crashes R:

x<-("A?")  
str_remove(x, "?")

How can I remove punctuation in strings?

(using R version 3.4.1; I note that stringr was build in v3.4.3)