fix: create change request with mv in v2

[Zaimwa9]

Thanks for submitting a PR! Please check the boxes below:

• I have read the Contributing Guide.
• I have added information to docs/ if required so people know about the feature.
• I have filled in the "Changes" section below.
• I have filled in the "How did you test this code" section below.

Changes

• Fix 400 on create-change-request
• Fix percentage_allocation not being updated with feature value change request
• Fix percentage_allocation not being up with segment override during change request
• Fixed visual bug with number of changes in variation
• Fixed value missing in change request segment diff

How did you test this code?

[cursor]

You have run out of free Bugbot PR reviews for this billing cycle. This will reset on February 10.

To receive reviews on all of your PRs, visit the Cursor dashboard to activate Pro and start your 14-day free trial.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
flagsmith-frontend-preview	Ready	Preview, Comment	Jan 13, 2026 2:54pm
flagsmith-frontend-staging	Ready	Preview, Comment	Jan 13, 2026 2:54pm

1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
docs	Ignored	Preview	Jan 13, 2026 2:54pm

[github-actions]

Docker builds report

Image	Build Status	Security report
ghcr.io/flagsmith/flagsmith-api-test:pr-6515	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-e2e:pr-6515	Finished ✅	Skipped
ghcr.io/flagsmith/flagsmith-api:pr-6515	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith:pr-6515	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-private-cloud:pr-6515	Finished ✅	Results ✅
ghcr.io/flagsmith/flagsmith-frontend:pr-6515	Finished ✅	Results ✅

[talissoncosta]

I found an issue on creating a new flag with CR disabled.
Can you check if you are able to reproduce it as well ?

[talissoncosta]

TEST V2 + CR

• I can enable/disable my flag
• I can update the value of my flag
• I can update the value of a MV option
• I can update the weight of a MV option
• I can create a MV option
• I can delete a MV option
• I can add a feature to a release pipeline
• I can create a Feature specific segment
• I can attach a Feature specific segment
• I can attach an existing segment
• I can disable all segment
• I can save my segments

[talissoncosta]

It looks great @Zaimwa9 . Thanks for handling that.
I've been thought the flows that were failing and it seems to be all done.