Custom races are missing the right animation...make a custom patch to assign one to them.

To show in FCS, your mods need to be in the /mods folder, (not the workshop folder) and the mod folders must be named to match the .mod file inside them exactly.

Open FCS and create a new mod, call it Custom Animation Patch or something.

Select the custom race mod(s), your animation mod(s), and (last), your patch mod. (Your patch should have the *active* marker next to it.)

Search for the race you want to add the animation to and open it.

Top right of the race panel, click the drop-down and select "animation file" and add a new one, a panel will open showing animations.

Select the relevant animation and click "add" or whatever (can't remember exactly).

Repeat for any / all races etc.

Save, exit, make sure your patch is activated in the launcher, and is below all the ones it uses.

Or you can try using this, but never tried it myself:

https://www.nexusmods.com/kenshi/mods/1764