Error when update crontab

By executing the whenever --update-crontab command, the following error returns:

/usr/lib/ruby/vendor_ruby/whenever/cron.rb:132:in `parse_as_string': Couldn't parse: 31557600 (ArgumentError)
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:112:in `parse_time'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:50:in `time_in_cron_syntax'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:42:in `output'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:36:in `block (2 levels) in output'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:35:in `each'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:35:in `block in output'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:34:in `each'
	from /usr/lib/ruby/vendor_ruby/whenever/cron.rb:34:in `output'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:151:in `block (2 levels) in cron_jobs'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:147:in `each'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:147:in `block in cron_jobs'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:146:in `each'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:146:in `cron_jobs'
	from /usr/lib/ruby/vendor_ruby/whenever/job_list.rb:65:in `generate_cron_output'
	from /usr/lib/ruby/vendor_ruby/whenever.rb:10:in `cron'
	from /usr/lib/ruby/vendor_ruby/whenever/command_line.rb:54:in `whenever_cron'
	from /usr/lib/ruby/vendor_ruby/whenever/command_line.rb:106:in `updated_crontab'
	from /usr/lib/ruby/vendor_ruby/whenever/command_line.rb:35:in `run'
	from /usr/lib/ruby/vendor_ruby/whenever/command_line.rb:6:in `execute'
	from /usr/bin/whenever:41:in `<main>'

My schedule.rb file:

every 1.year do
  rake "maintenances:renew"
end

Any ideas?

Reproduce the failure with the shown schedule.rb entry and whenever --update-crontab. Start in whenever/cron.rb at parse_time and parse_as_string, following the stack trace from the command-line entry point; done means a yearly schedule using 1.year generates crontab output without the parse error.