Garen's E does not properly work with certain items

Garen's new E scales with bonus Attack Speed from levels and items. Guinsoo's Rageblade and Sanguine Blade both give (conditional) bonus AS, yet Garen's E doesn't work with either. I assume it's that way because of Kaisa, Riot coded conditional bonus AS to not synergize with Kaisa(or with anyone, it seems), because then she could evolve her E mid-fight and lose the evolve once the fight ends. That is not a problem for Garen though, he should just simply spin based on the bonus AS from items and levels that he has when starting the spin. Rageblade is a suboptimal item on him anyway, not letting Garen use it is inconsistent and illogical, because once again, based on the current tooltips it SHOULD work. Either clarify the tooltips so that it's consistent, or let Garen use Rageblade and Sanguine Blade. Garen is meant to be a tankier bruiser that teamfights anyway - I don't see how opening up a different playstyle(splitpushing) through enabling Sanguine Blade would be a bad thing.