Native app for ios doesn't work properly on TestFlight

I’ve build ios native package my app on AppFlow and uploaded to testFlight.
Now, at the first time that I run the app on the device (installed from testFlight):
app dosen’t send in http request headers Cookie: JSESSIONID (which user get after sign in).
If I close the app and open it again, then work correctly. When I run my app directly by USB it works allways correctly too.
I’ve tried: - Download the app (TestFlight) -> open it (wrong) -> close it -> open it again (correctly)
The same version of this app works correctly on android native.