SF XM-L 5-mode lost all its power

A friend's L2P with SF XM-L T6 5-mode memory dropin lost all its "oomph!" recently.

It sports a voltage range of 3-6V and has worked well and entirely satisfactory with both CR123A lithium primaries and 18650-18700 Li-Ions for about eight months now.

Now, without warning, the amperage has suddenly dropped to a very low 0,08A on high mode, the lowest reading was 0,02A.

The blinky modes and memory all work fine, it feels as if the driver has lost most of its current regulators - I don't know since I have never dissected any SF pill and don't know how their drivers work, exactly. The light is really dim now; for comparison, a LD20 on its 8-lumens low mode is much brighter.

I'm not too experienced with electronics and SMD technology. Any idea what could possibly have been damaged?