Do English Essential boxes not allow for bilingual bonus?

Hi all, just wanted to crowd source an answer to my question of whether or not I am indeed eligible for the bilingual bonus even though I am sitting in an EE box.

I am an EC with CBC SLE results that I have had since I finished testing in 2021. While the box I am in is EE, I work primarily in external engagement in Quebec, and I am the only analyst on the team working on our French files since I hold a CBC language profile. I raised the fact I have never gotten the bilingual bonus with my manager a few times and each time was told that I was ineligible for it as I was technically hired into the EE box. Is this true? Why would that be the case if the bonus was meant to incentivize bilingualism in the PS?