I've had similar errors with the closing parentheses on multiple occasions that affected multiple lines in my htaccess.
One occasion was the Apache change from 1.x to 2.x.
Others were simply when updates were added.
In many instances I was able to resolved the issue after adding the otherwise unnecessary escape.
Most mass hosting sellers don't have a clue to the perils of htaccess and/or regex.
I had a host for about seven years with two guys that were sharp as knives and even they didn't grasp htaccess.