Timezone of Recurrence Time overriding Schedule Timezone

[jtbirney]

I came across some strange behavior when adding recurrence times. I did discover that the issue can be resolved by converting everything to the same timezone before adding recurrence times, but the actual behavior is not intuitive and I believe should be fixed.

Description: If a recurrence time is added in a different timezone than the start time of the schedule, the timezone of the recurrence time interferes with other rules.

To Reproduce:

timezone = "America/New_York"
start_at = Time.use_zone(timezone) { Time.parse("March 15 , 2021 11:00AM") }.in_time_zone(timezone)
end_at = start_at + 45.minutes
schedule = IceCube::Schedule.new(start_at, end_time: end_at)
rule = IceCube::Rule.monthly.day_of_week(start_at.wday => [1, 3])
schedule.add_recurrence_rule(rule)
schedule.occurrences_between(start_at, start_at + 3.months)

rtime = Time.parse("2021-03-29T10:00:00.000Z").in_time_zone("America/Los_Angeles")
schedule.add_recurrence_time rtime

schedule.occurrences_between(start_at, start_at + 3.months)

Expected Output:

[
  Mon, 15 Mar 2021 11:00:00 EDT -04:00,
  Mon, 29 Mar 2021 03:00:00 PDT -07:00,
  Mon, 05 Apr 2021 11:00:00 EDT -04:00,
  Mon, 19 Apr 2021 11:00:00 EDT -04:00,
  Mon, 03 May 2021 11:00:00 EDT -04:00,
  Mon, 17 May 2021 11:00:00 EDT -04:00,
  Mon, 07 Jun 2021 11:00:00 EDT -04:00
]

Actual Output:

[
  Mon, 15 Mar 2021 11:00:00 EDT -04:00,
  Mon, 29 Mar 2021 03:00:00 PDT -07:00,
  Mon, 05 Apr 2021 11:00:00 PDT -07:00,
  Mon, 19 Apr 2021 11:00:00 PDT -07:00,
  Mon, 03 May 2021 11:00:00 PDT -07:00,
  Mon, 17 May 2021 11:00:00 PDT -07:00,
  Mon, 07 Jun 2021 11:00:00 PDT -07:00
]