Deleting one standup deletes all standups on same time but on different days

[darues]

If you create two or more alarms at the same hour but on different days, when deleting one of them it deletes every alarm on that time.
Here's the example:

@me: create standup Monday@10:00
@hubot: Ok, from now on I'll remind this room to do a standup every Monday at 10:00
@me: create standup Tuesday@10:00
@hubot: Ok, from now on I'll remind this room to do a standup every Tuesday at 10:00
@me: list standups
@hubot: Here's your standups:
Time: 10:00 all Monday
Time: 10:00 all Tuesday
@me: delete standup Monday@10:00
@hubot: Deleted your 10:00 standup.
@me: list standup
@hubot: Well this is awkward. You haven't got any standups set :-/