Losing the game causes creatures with dynamic toughness to die.

In this game the Traxos player had Construct Tokens and Darksteel Juggernaught, both of which say they have power and toughness equal to the number of artifacts you control.
When the Traxos player lost the game, all permanents they controlled also left the game so they controlled no artifacts, this caused Darksteel Juggernaught and the Construct Tokens to somehow also die even though they had already left the game, which then caused Poison-Tip Archer to trigger.

Game log.

Start by reproducing the reported loss-of-game scenario with Traxos, Construct Tokens, Darksteel Juggernaut, and Poison-Tip Archer, using the attached game log as context. Trace how permanents leave play and how dynamic power and toughness are checked. Done means creatures that have already left the game do not die again or trigger Poison-Tip Archer.

Written by the indexing model from the issue text.