In merge request diffs overview foldables that hide unchanged code exist even if they blend out only one line

Summary

When being in the diffs/changes section of a merge request, the foldables that hide unchanged code even exist when they only hide one line.

What is the current bug behavior?

Foldables can contain only one line.

What is the expected correct behavior?

Foldables that only hide one line.

What is the expected correct behavior?

Foldables that only hide one unchanged line should not exist at all.

Happens for quite some time now but still observed with version 15.8.1 on a self-hosted gitlab-ce from the ubuntu repository on packages.gitlab.com.