I've tried the example project as is, with only the addition of B4XPages logs:
B4XPages.GetManager.LogEvents = True
This is the output:
** Activity (main) Pause event (activity is not paused). **
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
Using FileProvider? true
*** mainpage: B4XPage_Appear
** Activity (main) Resume **
** Activity (main) Pause event (activity is not paused). **
*** mainpage: B4XPage_Disappear [mainpage]
sending message to waiting queue (OnActivityResult)
running waiting messages (1)
** Activity (main) Resume **
*** mainpage: B4XPage_Appear [mainpage]
** Activity (main) Pause event (activity is not paused). **
*** mainpage: B4XPage_Disappear [mainpage]
sending message to waiting queue (OnActivityResult)
running waiting messages (1)
Orientation: 6
** Activity (main) Resume **
*** mainpage: B4XPage_Appear [mainpage]
It looks correct.