Thank you for reaching out and sorry to hear you're facing trouble previewing your design in XD. Would you mind telling us how it look in desktop preview? Please check if any blend modes is applied to the design. Is it possible for you to share the prototype link with us so that we can check at our end?
Nice to hear you're able to figure out the problem and thanks for sharing that observation. This will help our other customers to fix the issue. Please feel free to reach out to us in the future for any query related to XD.