AppendFile operation removes added line and everything below when uninstalling

In my installer I want to add a source call to the users ~/.bashrc. This works great by doing something like
 

component.addOperation("AppendFile", path_to_bashrc, "source my_file.sh\n")

Now the ~/.bashrc contains the source line and let's assume I manually add something to my bashrc below so that it reads:

# previous bashrc commands
source my_file.sh
echo "Some new line I added manually after the installation"

If I now run the uninstaller it removes not only the "source ..." line but also everything below it, i.e. the bashrc file would read

# previous bashrc commands

meaning it also removes the "echo ..." line which was not created by the installer. This to me is clearly not desired behaviour and imho should be fixed.

Thanks in advance,
Arno