Version prediction from git repository (commit count) broken after merge of branch.

[needleshaped]

Symptom: version prediction always results in 0.1.0.dev0 for ALL commits past merge commit 835e59c Merge branch 'develop' of gitlab.......-service into develop

git log --oneline --all --graph --decorate

* 1af294c (origin/develop, origin/HEAD) TEST: commit to test version.py
* ad8ab2d ...
* bcacad2 ...
*   835e59c  Merge branch 'develop' of gitlab.......-service into develop
|\  
| *   637e04c Merge branch 'feature/...' into 'develop'
| |\  
| | * b0361e8 ...
| |/  
* / 70b3501 ...
|/  
* 2774dc1 ...
...
(commits both in develop and feature/... branch)
...
| * 5ab611f (feature/...) FIX: ...
| * 5809732 FIX: ...
| * 5403ba6 REFACTORING: ...
| * 130a286 REFACTORING: ...
|/  

There are no GIT tags in directory.
Versioning is used to generate version with commit number only for CI: print(predict_version_str().split('+')[0]), resulting in e.g. 0.1.0.dev88 (from 0.1.0.dev88+2774dc19)

Example of LOGGING_LEVEL=debug on problematic merge commit:

⚓ 835e59c
LOGGING_LEVEL=debug python -m version_query -p .
DEBUG:version_query.version:version_query parsed version string '0.1.0.dev0' into <class 're.Match'>: {'release': '0.1.0', 'prerelease': '.dev0', 'local': None} ('0.1.0', '.dev0', None, None)
DEBUG:version_query.version:parsed pre-release string '.dev0' into ['.dev0']
DEBUG:version_query.version:version_query parsed version string '0.1.0.dev0' into <class 're.Match'>: {'release': '0.1.0', 'prerelease': '.dev0', 'local': None} ('0.1.0', '.dev0', None, None)
DEBUG:version_query.version:parsed pre-release string '.dev0' into ['.dev0']
0.1.0.dev0

Workaround: add tag, e.g. git tag v.0.2.0 on ANY commit in history, before, after merge in develop, or within merged branch itself.

Observation: putting tag before merge results in a commits in branch (reached via git checkout ) having it's separate versioning (instead of 2.1)
In this case with simple loop over git up && python -m version_query -p . I can confirm, that counter within branch change

Need to look into code and GIT structure/behavior to understand, what went wrong. It seems version-query can't traverse history with a merge back, and always assumes commit 0.
Any additional information I can supply to help?