Broken revision in hg mercurial?

Question

Delphi

Essence.
There is a certain revision of the utility in the default HG branch that was guaranteed to be built by the buildserver seven months ago. Let's call it 2028 (after its number).
At the same time, a neighboring branch was developing, the essence of which was code refactoring. It started from revision 712 and developed in parallel.
The assembled utility actively used those modules that were under refactoring in the neighboring branch, but naturally did not know about the changes made in them, because. the branch was not from her branch...
After some time, the need for the utility disappeared, and the branch with the refactored code was merged with the default one.
Literally today it was required to rebuild this utility again. Knowing that she doesn't know how to work with refactored code, I rolled back to her latest buildable revision number 2028 and saw that her build was not successful, because. it uses those modules that were changed in the neighboring branch 7 months ago, and not those with which it was originally built then.
Question.
How could the merging of two branches change modules that were developed in two parallel branches.
Those. what could lead to such behaviour?
Everyone on the team uses Merge, except for one employee who uses Rebase and who actually refactored the code.

Answer 1

No errors:
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
11263 files, 5495 changesets, 30488 total revisions