The syntax file for Ruby (
Ruby.sublime-syntax) contains a list of unresolved issues. Among them is:
text: "p << end print me! end" symptoms: not recognized as a heredoc solution: there is no way to distinguish perfectly between the << operator and the start of a heredoc. Currently, we require assignment to recognize a heredoc. More refinement is possible. • Heredocs with indented terminators (<<-) are always distinguishable, however. • Nested heredocs are not really supportable at present
So yeah, it's normal.