As per my initial comment on this pull request, line stripping has been moved to the final stage of file parsing in order to catch any trailing whitespace that could be added by further processing after the file is read (which consists of include-file inlining, line-continuation joining, and Jinja2 processing).  That makes this line an error (line continuation is now handled *before* stripping) unless we specifically allow line continuation characters to be followed by whitespace - as per my final comment https://github.com/cylc/cylc/pull/854#issuecomment-32330433