Problem with GNSS - delay in detecting satellites

Hello, 

i'm having a problem with the satellite detection time when I start gnss search. When I start the search, for a while at first the satellites are not detected and then they start to be detected. The delay time is often distinctive. I'm currently using gnss in single fix mode with a timeout of 65 seconds. In the nrf_modem_gnss_use_case_set() function, I'm using the flags NRF_MODEM_GNSS_USE_CASE_SCHED_DOWNLOAD_DISABLE and  NRF_MODEM_GNSS_USE_CASE_MULTIPLE_HOT_START. 

Details setup:
Modem FW: 2.0.2
SDK version: 2.8.0
Board: nRF9161 dk

Below are some examples that demonstrate the problem described:

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// 1º search //
[00:28:05.962,188] <inf> main: Searching... N. Satellites: 0
[00:28:06.962,829] <inf> main: Searching... N. Satellites: 0
[00:28:07.963,836] <inf> main: Searching... N. Satellites: 0
[00:28:08.964,904] <inf> main: Searching... N. Satellites: 0
[00:28:09.965,484] <inf> main: Searching... N. Satellites: 0
[00:28:10.965,881] <inf> main: Searching... N. Satellites: 0
[00:28:11.966,247] <inf> main: Searching... N. Satellites: 0
[00:28:12.966,918] <inf> main: Searching... N. Satellites: 0
[00:28:13.967,163] <inf> main: Searching... N. Satellites: 0
[00:28:14.967,529] <inf> main: Searching... N. Satellites: 0
[00:28:15.968,322] <inf> main: Searching... N. Satellites: 0
[00:28:16.968,627] <inf> main: Searching... N. Satellites: 0
[00:28:17.969,177] <inf> main: Searching... N. Satellites: 0
[00:28:18.969,390] <inf> main: Searching... N. Satellites: 0
[00:28:19.969,818] <inf> main: Searching... N. Satellites: 0
[00:28:20.969,940] <inf> main: Searching... N. Satellites: 0
[00:28:21.970,916] <inf> main: Searching... N. Satellites: 0
[00:28:22.971,435] <inf> main: Searching... N. Satellites: 0
[00:28:23.971,527] <inf> main: Searching... N. Satellites: 0
[00:28:24.972,015] <inf> main: Searching... N. Satellites: 0
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX


Sometimes no satellite is found during the search time. All tests were performed with the board located in the same place.

What could be the problem? Any suggestions?

Thanks,
GoncaloS