Added/registered iOS device was not found/gone missing

Appium Studion(v20.04.6801) is install on Windows 10 Enterprise.
Added an iPhone 7 to Appium Studio last week, and automating it without issue.
This morning as I login, the iPhone 7 is no longer registered (not found in the added list) with Appium Studio.
Normally, close and re-open Appium Studio, the added device will remain in the added list.
Why the added iPhone had gone missing from the added list, and need to be added again please? How can I prevent this from happening?

Not sure how is this issue related to the file Roaming\appiumstudio\app.properties; as it happens again (one week later) this morning, I notice that app.properties has just these few lines:

#Mon Aug 31 22:51:25 BST 2020
devices=
first.launch=false

It looks like somehow, this file was modified; and cause the added/registered iOS device to be not found.

Manually re-add/re-register the iOS device with Apple APP-SPECIFIC PASSWORDS, the following details were added to app.properties:

#Tue Sep 01 12:34:35 BST 2020
alias.xxxx\sss\ iPhone.is_emulator=false
alias.xxxx\sss\ iPhone.agentsecured=false
first.launch=false
alias.xxxx\sss\ iPhone.sn=<device SN>
alias.xxxx\sss\ iPhone.type=iPhone10_4
ios.debug.instrumentation.prop.0.time=1598955006042
alias.xxxx\sss\ iPhone.remoteagent=127.0.0.1\:27015
ios.debug.instrumentation.prop.0=C\:\\Users\\<usr>\\AppData\\Roaming\\appiumstudio\\apk\\prof0\\VE97N6S89D.p12;ENCRYPT\:464E526C697774714F564B4F4C526235496D5434715A47377A56576F722B7235476547394663544B356B68325469477453747A454D327932644C2F6755746842457A675934386C734253383D;C\:\\Users\\<usr>\\AppData\\Roaming\\appiumstudio\\apk\\prof0\\1598955005977.mobileprovision
devices=ios_app\:xxxx sss iPhone
<device SN>.enable-non-instrumented-mode=true
alias.xxxx\sss\ iPhone.host=usb

I.e. if I change app.properties to those three lines of text, restart the Appium Studio would have no device registered.

Would appreciate someone comment on this finding.