Reproduction steps:
1. Download and open attached project
2. Build it for Standalone
3. Open 2 instances of the game( or 1 and run the game in the editor )
4. Host the game with one of them
5. Connect with the other
6. Wait a few minutes

Expected result: online game continues as normal
Actual result: client disconnects from host

Note: If you add the user's script "ConnectionConfigFixer" to the "Networking" GameObject, which increases the NetworkDropThreshold, with that build the client no longer disconnects.

Reproduced on 5.2.3f1, 5.3.6f1, 5.4.1p3, 5.5.0b7, 5.6.0a1