"[Worker0] Local keyword space index cache out of sync." errors are thrown when upgrading the project

How to reproduce:
1. Create a new Unity project
2. Upgrade the project to the reproducible version and observe the results

Expected results: No errors are thrown
Actual results: Multiple "[Worker0] Local keyword space index cache out of sync." errors are thrown

Reproducible with: 6000.6.0a7

Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: No other environment tested

Full error:
[Worker0] Local keyword space index cache out of sync.
UnityEditor.AssetPreviewUpdater:CreatePreviewForAsset (UnityEngine.Object,UnityEngine.Object[],string)

Note: The bug was reproduced only once