Replacing the body of SimpleText::add with the following code appears to affect the transforms of objects drawn after the text.

        let brush = brush.unwrap_or(&Brush::Solid(Color::WHITE));
        self.add_run(
            builder,
            font,
            size,
            brush,
            transform,
            None,
            Fill::NonZero,
            text,
        );

This only occurs in some cases but seems to be deterministic. I suspect it has something to do with the glyph run resolve code but after a bit of investigation I haven't been able to track it down yet, so leaving this issue as a reminder.