When a user pushed a tag without pushing the commit itself, the commit will still be pushed to Bitbucket, and will still appear in Bitbucket via specific commit URL or the "All branches" tab, but does not appear on any specific branch's history.

Should be related to this bug: BCLOUD-12294

Steps to reproduce:
git clone git@bitbucket.org:mcastellini/possible_bug.git
cd possible_bug
echo "First Contributor" >> contributors.txt
git add contributors.txt
git commit -m 'First commit'
git push -u origin master
cd ..
git clone git@bitbucket.org:mcastellini/possible_bug.git possible_bug_other
cd possible_bug_other
echo "Second Contributor" >> contributors.txt
git commit -am "Second commit"
git tag dangling
git push origin --tags
cd ../possible_bug
echo "Third Contributor" >> contributors.txt
git commit -am 'Third commit'
git push origin master

Note:

• "/commits/branch/master" consistently shows the correct status of master.
• "/commits/all" ends up showing commits that do not belong to any branch, even though they are referenced by a tag; this might be confusing, but it is consistent with the output of git --log --oneline --graph --decorate --all on origin.
• "commits/dangling" shows the commit as belonging to master which at no point in time is true from the point of view of origin; if you were to run a git branch --contains dangling on origin you will get no output, meaning that it does not belong to any branch. This is IMHO the actual bug.