pptx reference doc exported from Keynote does not work

[rockola]

Explain the problem.
pptx document exported from Keynote can't be used as slide reference. Attempt fails with

Could not find a 0th placeholder of type obj (or nothing)

Steps to reproduce:

1. pandoc --print-default-data-file reference.pptx > pandoc-ref.pptx
2. open pandoc-ref.pptx to open pptx document in Keynote
3. Export document from Keynote as PowerPoint with the name refref.pptx
4. Create test.md - any doc will do, see below for example
5. pandoc test.md -o presis.pptx --reference-doc refref.pptx fails with the above message
6. pandoc test.md -o presis.pptx --reference-doc pandoc-ref.pptx produces output successfully

test.md:

% Test doc
% ORK
% 2024-04-03

# FOO

Bar

Pandoc version?
pandoc 3.1.12.3 from Homebrew
Keynote 14.0
macOS Sonoma 14.4.1 (Apple Silicon M1 Max)

[rockola]

Here are the Powerpoint files in question, pandoc-ref.pptx is the output of pandoc --print-default-data-file reference.pptx, refref.pptx is the same file after a round trip to Keynote.
pandoc-ref.pptx
refref.pptx