First frame is brighter than the rest

[mumle]

When I render a sequence the first frame will be brighter than the rest...

Using max 2021, vray gpu 2.3, nvidia driver 528.49

Any good ideas?

[hermit.crab]

Could you simplify the scene and attach it here so we can troubleshoot?

EDIT: I just noticed you wrote that your V-Ray is 2.3. Is this a typo? I'm asking since we do not provide support for such old versions.