AirPrime XA1130 units do not get GNSS data

We have the product where we use either XA1110 or XA1130 GNSS modules. The one with XA1110 works just fine, and are able to get the GNSS data without problem.
The XA1130 modules, on the other hand, are not able to receive the localization data, even being on and open sky for a long time:

Details about the unit in our product:

-> b'$PMTK605*31\r\n'
[RELEASE VERSION]: PMTK705,AXN_5.1.1_3333_17090119,8534,XA1130,1.0*34

The units always deliver wrong RTC date/time:

-> b'$PMTK435*30\r\n'
[RTC TIME]: PMTK535,2005,8,19,8,11,4*0A

No EPO data is stored in the chip:

-> b'$PMTK607*33\r\n'
[EPO STATUS]: PMTK707,0,0,0,0,0,0,0,0,0*2E

We use internal antenna:

-> b'$PGCMD,203*40\r\n'

We tried “default recovery”, “full cold start”.
Is there any special initialization procedure for the XA1130 to get it running?

Thanks in advance for a reply!