Upon export what are you FBX settings?
- Are you using bake animation with resample?
- Which version of the FBX exporter are you using (2020, 2019 etc)?
In the advanced options on import do you have a specific setting for custom sample rate?
(I have use custom sample rate un-ticked and sample rate set to 0 and all works as expected)
You can try ticking “use default sample rate” in animation → advanced. That should enforce a 30fps cap
Looking the import sample keys 60001 seems like you have a very long animation. Maybe your bake animation step size is very high? (I have mine set to 1)