'LandmarkRegistrationWidget' object has no attribute 'landmarksWidget'

Problem report for Slicer 5.6.2 win-amd64: [please describe expected and actual behavior]
‘LandmarkRegistrationWidget’ object has no attribute ‘landmarksWidget’
[CRITICAL][FD] 07.04.2024 18:00:56 (unknown:0) - libpng warning: iCCP: known incorrect sRGB profile
[CRITICAL][FD] 07.04.2024 18:00:56 (unknown:0) - libpng warning: iCCP: known incorrect sRGB profile
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - Traceback (most recent call last):
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - File “C:\Users\chao.wang\AppData\Local\slicer.org\Slicer 5.6.2\bin\Python\slicer\ScriptedLoadableModule.py”, line 263, in onReloadAndTest
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - self.onReload()
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - File “C:/Users/chao.wang/AppData/Local/slicer.org/Slicer 5.6.2/bin/…/lib/Slicer-5.6/qt-scripted-modules/LandmarkRegistration.py”, line 650, in onReload
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - slicer.util.reloadScriptedModule(“LandmarkRegistration”)
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - File “C:\Users\chao.wang\AppData\Local\slicer.org\Slicer 5.6.2\bin\Python\slicer\util.py”, line 1405, in reloadScriptedModule
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - widget.cleanup()
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - File “C:/Users/chao.wang/AppData/Local/slicer.org/Slicer 5.6.2/bin/…/lib/Slicer-5.6/qt-scripted-modules/LandmarkRegistration.py”, line 304, in cleanup
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - self.landmarksWidget.removeLandmarkObservers()
[CRITICAL][Stream] 07.04.2024 18:02:00 (unknown:0) - AttributeError: ‘LandmarkRegistrationWidget’ object has no attribute ‘landmarksWidget’