Is bedding necessary?

In Planet Zoo, the "beds and shelters" tab under ‘Habitats’ includes premade hard shelters and also bedding (piles of leaves and hay.) Adding the hard shelters to my habitats or excavating out of hills meets the "hard shelter" requirement for my animals — so what’s bedding used for?

As an example, I have an okapi who is showing 100% for all stats (except 99% for plants) — she’s perfectly happy:

… and yet looking at her habitat, she has hard shelter and no bedding. The habitat info panel shows this as "bad" (red indicator) … but does it really affect anything?

When I tried Googling what the purpose of bedding was, all I found were year-old guides about how to build hard shelter. Did the hard shelter requirement previously include something related to bedding? Is there some hidden game mechanic I’m not understanding?

I’m playing Franchise mode, hard — though I’ve seen the same behavior in scenario, sandbox, and challenge modes and all difficulties.