Trouble understanding why some non-branch lines are yellow in review

Description

A line containing “delete” is marked yellow and I don’t understand why. It isn’t a branch and it is surrounded by green so it must have executed.

Repository

Job: https://travis-ci.org/boostorg/uuid/jobs/539217521
Codecov: https://codecov.io/gh/boostorg/uuid/src/be5876a0fc9c2f7ad92eb95ba12e62d381e9068e/include/boost/uuid/random_generator.hpp#L130