Files automatically committed to other branches

We're using IntelliJ Community with Git. I'm working in 4 branches not accessed by anyone else. I made a change in one branch (call it A), commited/pushed. Pulled our Stage branch to import, into branch A, any changes from other team members who pushed to Stage. When I created a Pull Request for branch A, all commits from the other 3 branches automatically appeared in branch A. The same commits with the same date/time are in the intended branches. I'm the only one accessing these 4 branches. Has anyone seen this?