Somewhere when get_open_slots is called blocktime is not properly passed down and it resets to the default of 0…
For now I patched this by changing ./src/logic.php:77
from
$block_time = $time_now + $block_before * 60;
to
$block_time = $time_now + (int)$this->options->get_option_value('block.time', 0) * 60;
