Color and brightness difference from preview to final render

I'm working on a Premiere Pro Project and I've noticed a difference in color and brightness of one clip, comparing the preview and the final render. All the other clips work perfectly fine, but one keeps looking different. I will post the structure of the concerning clip below.

The pink AEP file is the countdown (Blend Mode to Overlay, 100% Opacity), which is scaled down to fit into the square of the "Old Film Projector" Layer (Blend Mode to Normal, 50% Opacity), the others are Effects (Blend Mode to Soft Light, 100% Opacity).

I've already tried the following solutions: Disable the effects layer(s), enable and disable the "Display Color Management" Setting in the preferences tab, enable and disable the GPU acceleration, try different Working Color Spaces under Sequence Settings. 

My export settings are: Format H.264, Render at Maximum Depth, Use maximum render quality, Performance: Hardware Encoding, Profile: Main, Level 41, Export Color Space: Rec.709, HDR Graphics White: 203 (75% HLG, 58% PQ) Bitrate Encoding 15 Mbps.

I'd appreciate an answer. Thanks in advance.