1. Here's why

If you are using the Hyperlight Effect, please note that Hyperlight is rendered with a shorter range for bouncing light rays in Movies and Image Sequences than on Photos.

For that reason, Hyperlight in Movies and Image Sequences will appear darker compared to Photos.

This is by design in order to keep render speeds high and noise low in Movies and Image Sequences.

Example of high range Hyperlight on a Photo rendered via the Current shot tab in Movie Mode:

Example of low range Hyperlight on a Photo rendered via the Image sequence tab in Movie Mode:

2. Workarounds

2.1: Consider adding the Global Illumination Effect to your Clip.

Please follow the advice in the article below in order to avoid flickering lighting:

Knowledge Base: Why does the lighting flicker in some videos?

Example of low range Hyperlight on a Photo rendered with a Global Illumination Effect via the Image sequence tab in Movie Mode:

2.2: An alternative to the Global Illumination Effect would be to add Omni Lights, or Area Lights facing upwards to simulate additional bouncing light rays.

Example of low range Hyperlight on a Photo rendered with an Area Light facing the ceiling via the Image sequence tab in Movie Mode: