"EndLayoutGroup" errors are thrown in console when GUI items are highlighted by PrefixLabel after highlighting by content in Highlighter.Highlight method. Refer the attached video

Steps to reproduce:
1) Create a new project
2) Import attached script "HighlighterTester.cs"
3) Window > Highlighter Tester
4) Select Highlight by content
5) Select Highlight by PrefixLabel

Actual result: "EndLayoutGroup" errors are thrown in console and GUI items are not highlighted by PrefixLabel

Expected result: No errors are thrown in console

Occurring on: 2020.2.0a7, 2020.1.0b6, 2020.1.0a24
Working fine on: 2020.1.0a23

Environment: Occurring on both Windows and Mac

Stack trace:
EndLayoutGroup: BeginLayoutGroup must be called first.
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)