I have bought two (different ones) and they both work the same way.
The light is turned ON before it can be turned into brake mode.
By turned ON, it means that it must functioning as a rear light and that means four modes of annoying red flashing which is not practical on a motorcycle as you need it to go from OFF to braked ON.
I have asked a few other sellers about theirs, and get mostly met with a "don't know" .
I'll post back if I find one that does what I need it to.
John "Josh" Nashwebmaster@arielownersmcc.co.uk
2009 royal Enfield,1978 t140 bonneville, '67 CJ750, 196-ish Ural M62 outfit, 1960 k750, ''51 kH500, ''49 soon to be Ariel bobber, 47 VH twinport, '44 Ariel WNG, '43 Ariel WNG, '41 Ariel WNG and piles of rusty scrap ....