Not able to promote work items past first stage: Rebase failures

**Describe the bug**
After deploying an approved work item to the first stage of our pipeline we try to promote the work item to the second stage and receive the error "Promotion Blocked: Promotion blocked due to dependency". We didn't receive any errors in the UI when promoting to the first stage - everything displayed as successful. Upon reviewing Activity History we noticed an error stating "Rebase of WI-XXXXXX branch from QA branch failed".

Once this error occurs the pipeline is stuck. I tried manually rebasing the branch and even though that is successful, the pipeline continues to throw the dependency error.

**To Reproduce**
Steps to reproduce the behavior:
1. Get 2 work items to approved state (New account field in each work item)
3. Promote one work item to first stage: Integration
4. Promote second work item to first stage: Integration
5. Try to promote second work item to second stage: UAT
6. Review error: Promotion Blocked
7. Click on Activity History
8. Review Rebase errors from Promotion to first stage
...

**Expected behavior**
After promoting to the first stage, we should be able to select any of the available work items and promote to the next stage

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Additional context**
Repository is set up under an organization. We created a brand new repository with branches for the test and checked settings to ensure we didn't have anything blocking rebases.