Unused format specifiers are not escaped.

[lm-sousa]

As detailed in an issue in our tool, when unused, a %s specifier will catch the timestamp inserted by this package.

specs-feup/clava#149 (comment)

Example:
Notice the second line of regular text and the first of debug's output.

I had a brief look at the codebase but could not find the source of the issue.
This was observed in version 4.3.4