All spell lore types are found on weapons as a suffix - except for one. Radiance lore is found on shields as a prefix instead. For all other types its thus possible to have the spell power bonus as a prefix and the lore as a suffix on a single weapon - but not so for light spell damage.
This very much appears to be a bug which I would greatly appreciate if you could fix. Thank you.
(no need for anyone to tell me that I should just use a blue armor for major lore, thats besides the point of this post)