@F.M. 

"When I transfer from one router to another while on 5Ghz my device drops internet and shows no internet at a times"

Can I have the model number of the clients that kept disconnection during Mesh roaming?

Were you able to reproduce this issue most of the time？

"my device drops internet and shows no internet at a time", is it still connected to WiFi but no internet or it has disconnected from WiFi already?

Will it connect back to the second M4 automatically later?

Please refer to this link to turn off "Mesh Technology" and "Beamforming" on the Deco APP:

Fix unstable connection when connected to the Deco network (Case3)

Wait for your reply.

Best regards.

  @David-TP after i saw my network gone i have to restart my phone wifi then it will be ok...