Host go Offline in Android 9 after 10 sec.

S9+ Pie Patch June, after reboot the device is Online (for a certain variable period of time, apparently without a logic) but if you open Host App (from 14.1.84 HM to 14.4.183 HM) even just once, the device keep Online (Assigned) only if you open Host again and keep it open, if you move to another App the device keep Online status in TeamViewer for Remote Control (Win10 / Android 7/9) only for 10 sec. then disappair. Previous versions works well but the Add-On is not up to date.
Host device remains Online in my Account also if the Assignement is removed.
Eco Mode, disabled but that seems to work well (difficult to verify if you don't notice any disconnections), could be the cause of the problems in these versions of Host, I think. In the 10 minutes before standby (blue monitor that will turn yellow in Eco mode), about 2:30 or 5/8 min. after the connection is closed, the monitor that identifies the device change for a few seconds from blue to yellow.
I've tried everything (Smartphone and App).
Thank's.
Manolo