Can it be disadvantageous to actively publish in completely different fields? I'm a researcher in a STEM field and work at an institute where research staff salaries (including mine) are dependent entirely on third-party grant money. I've already successfully obtained research grants and served as the PI for a few projects.
In my spare time (i.e., after I go home for the day) I very much enjoy reading and writing about topics in the humanities, and I have recently had contributions on these topics published as peer-reviewed articles in humanities journals. In retrospect I wonder whether having published in these venues was a good idea.
The problem has to do with my current and future grant proposals; some funding agencies require proposals to include a CV listing all of the applicant's peer-reviewed publications in the past n years.  (And even for those agencies without such a rule, the reviewers can easily find all my publications online if they care to look.)  I am wondering how the presence of my non-STEM publications will be viewed by the STEM proposal reviewers.  Are these publications going to be interpreted negatively, as a lack of research focus on my part?  Where feasible, should I include an explanation in my proposal CVs that these publications were avocational (and if so, how should I word this)?  Should I entirely give up my beloved hobby of writing for humanities venues in order to better secure my funding prospects as a scientist?  Or are my fears here entirely misplaced, there being no downside at all (or maybe even some benefit) to having the occasional humanities article in my publications list?
Two further things to note:

I realize that there are a couple possible workarounds that I might try, such as using a pseudonym when publishing in the humanities, or simply omitting the humanities publications from the CVs I include with my grant proposals.  However, both of these necessarily involve some deception or bending of the rules, and in any case won't take effect for the proposals I've already got under review.

There are already a couple of questions here about publishing in foreign fields (Can I publish in a field completely unrelated to my present field?, Is it good reputation for a researcher to publish an article belonging to different research field?), though these are from students who haven't yet started their PhD.  My question is more about how an unorthodox publication list will affect STEM research grant applications specifically, for an applicant that already has a doctorate and some project lead experience.
I've served as a referee on grant proposals to large public-sector research funding bodies on a couple of occasions.  If a PI had demonstrated the ability to achieve peer-reviewed publications in another discipline as well as in the discipline most directly related to the proposed research, I would be inclined to view that favourably.  But that doesn't necessarily mean that every referee feels the same.