Docker Tests failed by checks Timezone UTC

For about 2 weeks my tests fail. I always test my Dockerimages on the correct time zone. Exactly this has not been going on for about 2 weeks.

My Tests:

    @test "check timezone" {
        run docker run docker-image date +%Z
        [ $status -eq 0 ]
        [ "$output" = "UTC" ]

The Output:

    bats --tap tests/tests.bats
    not ok 1 check timezone
    # (in test file tests/tests.bats, line 4)
    #   `[ "$output" = "UTC" ]' failed

    bats --tap tests/tests.bats returned exit code 1

On Travis or localy runs the Tests fine