A runtime figure is not wrong. It is measured to a convention that means something quite different from what a buyer assumes.

The convention

ANSI FL1 quotes runtime until output falls to ten percent of initial.

A torch at nine percent of its headline brightness is still inside its stated runtime.

Regulated versus direct drive

A regulated driver holds output roughly flat, then drops off at the end.

Direct drive starts at the headline and declines from the first minute.

Heat does the rest

A small aluminium head cannot shed much power, so high modes step down thermally.

That is correct engineering, and it is why the first thirty seconds are not typical.

So ask a different question

Not how long it runs, but how long it holds a stated output.

That single change of question tells you more than any lumen figure on the box.