1. Create a file in a language for which syntax highlighting is available in SourceTree (I experience this bug with .sql files) and don't end it with a newline character.
2. Add the file to a repository
3. View the file diff (for the file add) in SourceTree

After the last numbered line in the file, the diff displays:

\  No newline at end of file

For .sql files, the line reads with at end of file coloured in blue as if they were part of the file syntax. The notice should appear all in one colour.

Reproduced in SourceTree 3.3.6, not 3.2.2, but Jira doesn't seem to permit this as an option.