Mixing frame rates

Hello and thank you in advance for taking the time to help!

I’m working on a project using Toon Boom 8.1 with the following settings 1998 x 1080p @ 30fps.

We export at 30 fps with key frame at 48 using the Animation codec.

This file is then brought into premier pro to be used with other footage at 24fps.

In premier everything appears okay at first but when I jump around the timeline I get missing frame errors all over.

How can I get the 30 fps exported animation to 24 fps to work better in a 24 fps Primere Pro timeline?

I’m currently using Premier to convert the animation from 30fps to 24fps.