[O] Vertical bars in org file break export to ics

[michael]

Hello list,

for the following *.org file running org-icalendar-export-to-ics will fail
with "Args out of range: [nil nil], 2".

* This is a test
  <2020-01-01 Mi>

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The error also occurs without any personal configuration files loaded
using the following software versions:

- Org Version: latest from org-mode.org
- Emacs Version:26.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.8)
of 2019-04-12

(The reason i have these vertical bars in my files is that i tend to use
graphics created with Emacs artist mode for the purpose of network
documentation.)

Is it me or could this be an org-mode bug?

Thanks for your effort in advance!

Michael