Inactive timestamps show up in agenda

[Michael Maurer]

Both <2024-04-04 Do> and [2024-04-04 Do] show up in Agenda-View.
Google couldn't really help me on that, and I'm thinking maybe there's
a flag I set to include every timestamp in Agenda? I don't know.

For reference, the entries look like this:
* TEST
<2024-04-04 Do>
[2024-04-04 Do]

shows as

Thu       4 Apr 2024
 TEST
 [ TEST

Yes, there's no closing square bracket.