OpenHAB2 RC1: BUG? Nested group with SUM function not changing icons

HI everyone.

I am close to the end of the migration from OH1 to OH2 RC1.
Now I stumbled upon a strange behavior with the nested groups using the AND function on Contact items. I have other nested groups using the SUM function, those work fine.
With OH1 the following is working perfect, but with OH2 RC1 the icon of the group is not changing in ClassicUI or homeDroid. Even after manually reload the page the group is just showing the basic from of the icon.

Here is the items file part:

Group:Contact:AND(CLOSED, OPEN) Verschluss			"Verschluss [MAP(]"					<lock>
Group:Contact:AND(CLOSED, OPEN) Verschluss_UG 		"Verschluss Untergeschoss [MAP(]" 	<lock>	(Verschluss) 
Group:Contact:AND(CLOSED, OPEN) Verschluss_EG		"Verschluss Erdgeschoss [MAP(]"		<lock>	(Verschluss)
Group:Contact:AND(CLOSED, OPEN) Verschluss_OG		"Verschluss Obergeschoss[MAP(]"		<lock>	(Verschluss)

All items in these groups are Contacs
The sitemap part is simple as well:

Group item=Verschluss valuecolor=[!=CLOSED="red"]

The group logic itself is working fine as you can see from the event log. Verschluss_EG_Haustuer is a contact item which is member of the Verschluss group.

2017-01-19 17:43:12.396 [GroupItemStateChangedEvent] - Verschluss changed from CLOSED to OPEN through Verschluss_EG_Haustuer
2017-01-19 17:43:12.397 [ItemStateChangedEvent     ] - Verschluss_EG_Haustuer changed from CLOSED to OPEN

The text status of the item in the sitemap is changing perfectly. But the icon is not.

The issue is independent from the SVG or PNG setting.

Thanks a lot