UTM 9.375005 Wireless Bug?

Hey Guys, 

my architecture is:
one softwareappliance with 2 access points (ap15, ap30) site2site connected with another utm softwareappliance with one access point (ap30)

Since i've updated the two appliances from 9.355-4.1.1 to 9.375-1.5.1 iam not able to get run my access points.
debugging wireless log shows :

2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP100X: 9400-53d3a7b
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP15: 9400-53d3a7b
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP15C: 9400-53d3a7b
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP30: 9400-b2f252d
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP5: 1
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP50: 9400-b2f252d
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP55: 9400-53d3a7b
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for AP55C: 9400-53d3a7b
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] new firmware detected for RED15w: 1
2016:03:14-23:55:05 astaro awed[7713]: [MASTER] access point firmware available: AP15C:9400-53d3a7b AP10:9400-b2f252d AP55C:9400-53d3a7b RED15w:1 AP5:1 AP30:9400-b2f252d AP100C:9400-53d3a7b AP100X:9400-53d3a7b AP50:9400-b2f252d AP55:9400-53d3a7b AP15:9400-53d3a7b AP100:9400-53d3a7b
2016:03:14-23:55:10 astaro awed[7713]: [MASTER] SSID: MYWLANSSID is enabled and next time it is checked for being disabled is 1458003600.
2016:03:14-23:55:10 astaro awed[7713]: [REPORTING] updating rrd file for WLAN0 with 0 clients
2016:03:14-23:55:10 astaro awed[7713]: [REPORTING] updating rrd file for WLAN1 with 0 clients
nl80211 not found.
nl80211 not found.
nl80211 not found.
nl80211 not found.

the "nl80211 not found." comes every 30seconds.
I've scanned the traffic on access point Switchport in portmirroring mode with following results:

72178 1528.310516 0.0.0.0 224.0.0.1 IGMPv2 64 Membership Query, general [ETHERNET FRAME CHECK SEQUENCE INCORRECT]
Frame check sequence: 0x00000000 [incorrect, should be 0x9b68b078]
FCS Bad: True
Expert Info (Error/Checksum): Bad checksum

I've recovered the ap's with recovery tool but still no luck. Any hints?