notarized, identity cannot be confirmed

Hi, I'm trying to distribute an app..

With my Dev ID app cert I've succesfully signed and notarized the .app, then packed to dmg and signed and notarized it.

both stepled.

checking app with

spctl -a -v myApp.app

result:

myApp.app: accepted 
source=Notarized Developer ID

then checked the dmg

spctl -a -t open --context context:primary-signature -v my.dmg

result:

my.dmg: accepted
source=Notarized Developer ID

seems like everything is ok.

Now, according to this https://help.apple.com/xcode/mac/current/#/dev1cc22a95c I'm testing the launch behavior:

- uploaded dmg file to google drive, then downloaded.

- opened dmg and copied app to Applications folder.

- trying to run it and see the message "'myApp' can't be opened because the identity of developer cannot be confirmed."

Checking downloaded app from apps folder with spctl still says Notarized Developer ID.

Even checked it with check-signature tool, result:

(c) 2014 Apple Inc.  All rights reserved.
YES

also used advice from this forum(after gatekeeper message appeared):

log show --info --predicate "process =='XprotectService' and composedMessage contains 'rPathCommand'" --last 10m

result:

Filtering the log data using "process == "XprotectService" AND composedMessage CONTAINS "rPathCommand""
Skipping debug messages, pass --debug to include.
Timestamp                       Thread     Type        Activity             PID    TTL 
--------------------------------------------------------------------------------------------------------------------
Log      - Default:          0, Info:                0, Debug:             0, Error:          0, Fault:          0
Activity - Create:           0, Transition:          0, Actions:           0

What's wrong with it?

macOS Mojave 10.14.6