[Bug] Experiment-linked feature flag revisions are discarded after adding multiple flags

Summary

When linking multiple feature flags to a single experiment, some flags display the following warning:

The draft revision linking this experiment was discarded. The experiment-ref rule is no longer queued. I was able to reproduce this consistently after adding the 9th feature flag. The intended experiment contains 16 linked flags.

Seems to be related to this PR- https://github.com/growthbook/growthbook/pull/4051

Steps to reproduce

Create an experiment. Link feature flags to the experiment one at a time. Continue until at least nine feature flags have been added. Review the linked flags on the experiment page.

Expected Behavior

All feature flags should remain linked to the experiment, with their experiment-ref rules correctly queued or published. Adding additional flags should not discard previously created revisions.

If there is a supported maximum number of feature flags per experiment, the UI and API should validate and clearly communicate that limit.

Current Behavior

After approximately nine flags are added, some linked flags are marked as Discarded and display:

The draft revision linking this experiment was discarded. The experiment-ref rule is no longer queued.

However, when opening the affected feature flag, its experiment rule appears to be configured correctly. It is therefore unclear whether this is only a stale UI/reference state or whether the flag is no longer properly linked to the experiment at runtime.