That was certainly the case with the final season of Samurai Jack, which aired on Adult Swim, where restrictions are a lot lighter (although there are rules) and allow for certain shows that typically wouldn’t air during Cartoon Network’s standard programming hours.
Watership Down (which got a remake on Netflix not that long ago) may be an apt enough comparison in regards to Primal, as the “violent” descriptor could tease this adventure is geared more towards adults than younger audiences.