Setting aside the fact that we apparently need to understand Russian to know whether Truss was talking over an interpreter and the suggestion that maybe that footage has been rigged by a pro-EU group...
Truss walked into a deliberate (and, yes, childish - ooh, look, both sides were behaving poorly, can I cope with that complex notion?) trap set by Lavrov, who fooled her into stating repeatedly that she thought Russia had no sovereignty over Voronezh and Rostov.
Sovereignty is surely meant to be one of this government's specialist subjects - although perhaps not Truss's, if she's a pesky Remainer just pretending to agree with Brexit to climb the greasy pole, after all...
But if she didn't know where Voronezh and Rostov are, she should not have doubled down on that. There are ways of sidestepping those questions without looking like an incompetent moron.
Meanwhile, thanks to clav for the belly laugh at "Macron and Putin are friends". There are some comedy gems on here.