When a TITLE statement includes a null character string and formatting options, such as HEIGHT or FONT, the following WARNING will appear in the SAS log:

WARNING:  The TITLE statement is ambiguous due to invalid options or unquoted text.

The following TITLE statement replicates this behavior:

    title height=8pt '';

Without the formatting options, the WARNING is not generated. In either case, the TITLE text appears as a single quote in the output. The workaround is to add a blank space between the single quotes.