Bug report: Merging silently failed

Dear developers,

I merged https://observablehq.com/@kreijstal/abc into https://observablehq.com/@thsoft/abc (as the caption says). However, it clearly did not succeed: the two versions are different. Furthermore, if I click on ‘View changes’, the comparison shows Version 43 vs. Version 43; I think it should be two subsequent versions. Also, I can’t merge https://observablehq.com/@kreijstal/abc again, I can only fork it.

What could have gone wrong, and how can I really merge the changes into my notebook?

Thank you in advance,