Power BI JSON Theme not holding for all visuals

My team uses a custom JSON theme to manage our branding and color schemes. However, in our current Power BI report, when we apply our Custom JSON theme, save the PBIX file, close, and reopen the visuals have changed colors (while retaining the overall theme).

We currently use more than 8 colors in our JSON theme file, could this be why we're experiencing shifting of colors when we reopen the file?