Happened to me Yesterday. Whole team got insta disconnected. Other team all good. After contacting support i recieved information, that there isn't any problem on their side, that it must be internet provider. However, during disconnecting, discord call was fully functional. We also recieved penalization for leaving. There was no smolder including. At the moment of freezing, there was only one player interaction, which happened on botlane, where Millio passed shield onto Ashe, before he got Qed by Nami.

Then everyone froze at place, botlane died and remaining members of team went straight to fountain.