Why does '.el7' get duplicated while building the rpm file using spec in Red Hat Enterprise Linux 7?

Issue

• Trying to build a custom rpm file, where Release is defined as follows in spec file.

Release: 3%{?dist}

• Everything works as expected. %{dist} becomes part of the produced file name, eg, foo-1.2-3.el7.noarch.rpm etc. And, if the following is used:

Release: %{?release}

• It gets a name sans %{dist}, eg, foo-1.2-3.noarch.rpm.
• However, if the following is used, the .el7 gets duplicated. That is, foo-1.2-3.el7.el7.noarch.rpm, why?

Release: %{?release}%{?dist}

• What is wrong? How can one get a parameterized release number with just one instance of the %{dist}?