George isn't throwing shade. This is only a possibility for why their last stint was so disastrous. What changed? They overcooked the plank wear and to avoid disqualification they raised ride height and slowed top speed. It's not throwing shade, it's how George suddenly could catch and have several overtake opportunities. It's not like suddenly Leclerc got slow or George got fast. The car changed.

In the last stint Leclerc was corrective steering based on input telemetry in corners more while going slower. It's rationale to suggest less downforce. Lastly there's only two things they can change at pit stops, tyres and front wing. Nothing else legally or time wise can be changed. It's unfathomable to think they'd change the front wing on the race leading car. But ride height seems plausible, via more air in the tyres.

In other words George is likely right in his attempt to explain his sudden speed delta compared to leclerc.

Edit: Personally I bet the high pressure tyre was desperate if that's the case. High pressure tyres make less contact with the road and decrease grip. So whatever fraction of height they gained they no doubt lost not just downforce from height but lateral traction capability in the tyre itself.