REST API 404 using logbook with timestamp

I’m attempting to use the REST API and am having trouble (404 response) while trying to use a timestamp along with the logbook endpoint.

I can successfully reach this end point: /api/logbook.

However, I get a 404 response when trying this one: /api/logbook/2023-05-04T00:00:00+00:00/ (with or without the trailing slash).

The documentation shows this:
/api/logbook/<timestamp>

The <timestamp> (YYYY-MM-DDThh:mm:ssTZD) is optional and defaults to 1 day before the time of the request. It determines the beginning of the period.

The documentation has this url in a curl example:
http://localhost:8123/api/logbook/2016-12-29T00:00:00+02:00

Version info:
Home Assistant 2023.1.2
Supervisor 2023.04.1
Operating System 10.1
Frontend 20230104.0 - latest

Am I misinterpreting the documentation?

I can get this working by dropping the TZD (+00:00). My best guess is that the implementation doesn’t match the documentation.