This fix works for me.

    commit 6107c2b15bf19ab5300c2861db365a3dc310adc6 (origin/maint)
    Author: Nicolas Goaziou <mail@nicolasgoaziou.fr>
    Date:   Mon May 10 18:00:58 2021 +0200

         Revert "agenda: Fix "org-duration-to-minutes: Invalid duration
    format" error"

         This reverts commit bc857bfc62ba94e04fb338bfb35f4b612c114d0c.

         The "fix" breaks elsewhere, as reported below.

         Reported-by: Daniel Ortmann <daniel.ortmann@oracle.com>
    <http://lists.gnu.org/r/emacs-orgmode/2021-05/msg00592.html>


On 5/10/21 9:25 AM, Nicholas Savage wrote:
> Thanks for the report. This was also reported last night too: https://urldefense.com/v3/__https://lists.gnu.org/archive/html/emacs-orgmode/2021-05/msg00592.html__;!!GqivPVa7Brio!Non_TqJOEgfushDGmmgrZySe4dyz4pr69tdmeFRzKzRUwzoLORtfh7pMyW2pU_1ZotQ$
>
> I'll probably have a chance to look into this sometime today, but it probably won't be until this evening if anyone else has a chance earlier than that.
>
> On Mon, May 10, 2021, at 09:54, Detlef Steuer wrote:
>> Am Mon, 10 May 2021 16:45:30 +0300
>> schrieb Jarmo Hurri <jarmo.hurri@iki.fi>:
>>
>>> Greetings.
>>>
>>> To get my work done, I had to switch from master branch to stable, but
>>> now I started getting "invalid duration format" error when trying to
>>> create my daily agenda:
>>>
>>> org-duration-to-minutes: Invalid duration format: #("12:45-14:15 +1w"
>>> 0 15 (fontified nil org-category "schedule"))
>>>
>>> Here is the corresponding row, and the preceding row, from file
>>> schedule.org:
>>>
>>> <2021-04-15 Thu 09:15-10:45 +1w>
>>> <2021-04-19 Mon 12:45-14:15 +1w>
>>>
>>> Any hints?
>>>
>>> Jarmo
>>>
>>>
>>
>> Can confirm!
>>
>> Detlef
>>
>>
>> -- 
>> "Wozu leben wir, wenn nicht dazu, uns gegenseitig das Leben
>>   einfacher zu machen. (George Eliot)"
>>
>> Dr. Detlef Steuer
>> Helmut-Schmidt-Universität
>> Fakultät WiSo
>> Holstenhofweg 85
>> 22043 Hamburg
>>
>> Tel:  040/6541-2819
>> mail: steuer@hsu-hh.de
>>
>>