When I inject the Biab tracks into Reaper it don't put in any crossfades where there is item overlap, but if I move it then it will add auto crossfade, not sure where you would have these with a consolidated wav file unless you have rendered the section separately. There is only a tiny fade in out added to an item to turn the volume down at that point, this should not effect the tone of the rest of the wav file.
There are scripts/actions to automatically remove fades/crossfades from all items.

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