I recently noticed that if the drone's motors are started whilst the app is logged out the corresponding .txt flight log mentions that the app is logged out.
If you keep your flight logs it might be an idea to perform such a 'flight' and add
"_logged_out"
to the corresponding log's name.

NOTE the use of "_" instead of a gap.

You might need to move the log from your screen device to a computer then change the name of the file/log on the computer and copy the file back to the screen device.

For me Windows will not change the name of a .txt flight log whilst it is in/on an Android phone but Linux will change the log's name in/on an Android phone. I have no idea about a Mac nor an iPhone.
I have not tested to see whether Android itself permits you to change the log's name.

Regarding "NOTE", I have a vague recollection that the App does not like gaps in the name of the .txt flight log, hence the use of "_", but I won't swear that that recollection is accurate but gaps are best avoided IMO.

What's the purpose of this?
A search run on the screen device using its own file browser for "logged_out" might well find all your logged out flights and give you some sort of pattern but I was thinking mainly of anyone that at least looks at their logs' titles on their screen device via computer. You CAN run searches of the phone from a computer so you might be able to do the same with a 'smart controller'.

Alternatively
If you use Airdata I guess the 'logged out' message will appear in the replay of each affected flight.
The actual message that I see in a Phantomhelp csv is "Account not logged in." so the Airdata message may also be  "Account not logged in".
If you use flightreader or Phantomhelps' log viewer to process your .txt flight logs and use Windows there might be a means of scanning the resulting csv's for the text "Account not logged in."
"Find" perhaps?
If you use Linux or a Mac I am pretty sure you could play with "grep" in a terminal to scan your csv's.

Me?  I added a bit to my logbook program and found 14 logged out flights but some of those were deliberate log outs so I haven't looked for a pattern.

One thing I have noticed it that if you use multiple screen devices logging out on one device WILL log you out of the other devices once they connect to the internet

I recently noticed that if the drone's motors are started whilst the app is logged out the corresponding .txt flight log mentions that the app is logged out.
If you keep your flight logs it might be an idea to perform such a 'flight' and add
"_logged_out"
to the corresponding log's name.

NOTE the use of "_" instead of a gap.

You might need to move the log from your screen device to a computer then change the name of the file/log on the computer and copy the file back to the screen device.

For me Windows will not change the name of a .txt flight log whilst it is in/on an Android phone but Linux will change the log's name in/on an Android phone. I have no idea about a Mac nor an iPhone.
I have not tested to see whether Android itself permits you to change the log's name.

Regarding "NOTE", I have a vague recollection that the App does not like gaps in the name of the .txt flight log, hence the use of "_", but I won't swear that that recollection is accurate but gaps are best avoided IMO.

What's the purpose of this?
A search run on the screen device using its own file browser for "logged_out" might well find all your logged out flights and give you some sort of pattern but I was thinking mainly of anyone that at least looks at their logs' titles on their screen device via computer. You CAN run searches of the phone from a computer so you might be able to do the same with a 'smart controller'.

Alternatively
If you use Airdata I guess the 'logged out' message will appear in the replay of each affected flight.
The actual message that I see in a Phantomhelp csv is "Account not logged in." so the Airdata message may also be  "Account not logged in".
If you use flightreader or Phantomhelps' log viewer to process your .txt flight logs and use Windows there might be a means of scanning the resulting csv's for the text "Account not logged in."
"Find" perhaps?
If you use Linux or a Mac I am pretty sure you could play with "grep" in a terminal to scan your csv's.

Me?  I added a bit to my logbook program and found 14 logged out flights but some of those were deliberate log outs so I haven't looked for a pattern.

One thing I have noticed it that if you use multiple screen devices logging out on one device WILL log you out of the other devices once they connect to the internet