mute for 5 seconds while Strict RTP learning

Here is my system
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Whenever I go to PJSIP Settings and click SAVE (even if I did not change something) and then click to reload the settings, there sometimes is an error in the next call. The system tries to

0x7fb780175020 – Strict RTP learning complete - Locking on source address 195.185.37.60:35422
0x7fb780028430 – Strict RTP learning complete - Locking on source address 95.222.217.106:5742

When this is coming up the system is muted on the first about 5 seconds.
2 or 3 times later the systerm dooes not try to learn and switches to the source address immediately. The muting is then not there.

Best regards
Matthias