Incorrect crontab generated when using "days after/before"

Chronic correctly parses the following:

> Chronic.parse('4 days after start of month at 1pm')
=> 2021-10-05 13:00:00 +0200

However, the crontab the following generates:

every 1.month, at: '4 days after start of month at 1pm' do
  rake "execute_some_task"
end

Is incorrect:

0 13 1 * * /bin/bash -l -c 'cd /home/path/to/project && RAILS_ENV=development bundle exec rake execute_some_task --silent'

As it schedules the job for the 1st day of every month instead.

• This example is just to simplify the issue for illustrative purposes, in reality I'm attempting to have the job run 4 days before the end of the month, but that comes with its own nuances.

Reproduce the issue from the Whenever DSL example using “4 days after start of month at 1pm,” then compare its generated crontab with Chronic.parse's result. Trace how the DSL expression becomes the cron day-of-month field; done means the generated schedule runs four days after the month's start rather than on the first, with the end-of-month case considered separately.