Experience Builder 1.13 should be coming to Developer Edition soon, it will be based on on the 4.28 version of the API. This update removes watchUtils as they have been deprecated and replaced with reactiveUtils. All custom widgets using watchUtils will break with this update. If you are using any widgets older than Experience Builder 1.8, they will almost certainly be affected.
https://developers.arcgis.com/javascript/latest/release-notes/#breaking-changes
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