[bug]: Race condition causes duplicate sequence_id when creating issues concurrently via API

[backslash-ux]

Is there an existing issue for this?

• [x] I have searched the existing issues

Current behavior

When I create multiple issues concurrently via the Plane API (MCP integration), the sequence_id field gets duplicated across different issues. This causes:

1. Multiple issues share the same readable identifier (e.g., two issues both have MITRA-4)
2. The get_issue_using_readable_identifier API endpoint returns a 500 error for affected identifiers
3. The issue list in the UI shows duplicate sequence numbers

Example from my project (29 issues created):

• sequence_id 4: 2 issues (should be unique)
• sequence_id 14: 2 issues
• sequence_id 15: 2 issues
• sequence_id 17: 2 issues
• sequence_id 18: 2 issues
• sequence_id 22: 2 issues

What I expect is each issue should have a unique, auto-incrementing sequence_id that becomes the readable identifier (PROJECT-1, PROJECT-2, etc.).

Steps to reproduce

1. Use the Plane API to create multiple issues in parallel (e.g., 5 concurrent POST requests to /api/v1/workspaces/{workspace}/projects/{project}/issues/)
2. Check the created issues' sequence_id values
3. Observe that some issues share the same sequence_id
4. Try to fetch an issue with a duplicated sequence_id using GET /api/v1/workspaces/{workspace}/projects/{project}/issues/?identifier={sequence_id}
5. See 500 Internal Server Error

Environment

Production

Browser

Other

Variant

Self-hosted

Version

v1.1.0