Different lightning from Studio to Player

[SeargentAUS (Seargent)]

This is likely caused by the Unified Lighting beta feature:

Let There Be (Unified) Light! Unified Lighting Enters Studio Beta

Hello Creators, Roblox is committed to providing an exceptional user experience for everyone, no matter what experience they jump into or what device they’re using. This is why we prioritize building a platform that adapts seamlessly – and that includes how we handle lighting. Our vision for lighting on Roblox is that it scales smoothly across all devices, empowering you to achieve visuals true to your artistic intent without compromising on performance. To help bring this vision to life, we’…

It currently changes the lighting in Studio but does not yet copy into an actual game.
You can test this by looking in Files → Beta Features in Studio, then disabling Unified Lighting