The First: FontUpdateTracker.cs line 9 code: static Dictionary<Font, List<Text>> m_Tracked = new Dictionary<Font, List<Text>>(); The Font is referenced by m_Tracked always, never released! the issue cause font-resource leaked when the font are built as assetbundle The Second: unity3d 4.6.2 only error: modifications.empty() reproduce: 1. Create a canvas prefab with a slider 2. Drag the prefab to Hierarchy or PrefabUtilty.InstantiatePrefab(canvasPrefab)
Best to log those as issues on the UI Bitbucket repo. THey won't be picked up as bugs here. Or better yet, log them using the Unity bug reporter.