I checked this out on v.14 - running the save without alteration, indeed the BVR logic is ignored and the Su27 follows its course at 480kn during the engagement.
However, the "Ignore plotted course when attacking" was set to "No", as the A/C is not assigned to any particular mission.
On changing this to "Yes", the expected BVR logic was present.
With "Ignore plotted course when attacking" is set to "Yes", the Crank behavior is seen with the A/C slowing to Loiter and cranking, and also, when set to "follow missile straight in", the Aircraft now accelerates to full burner on the run-in to, closing the distance even further.
In the original save as-provided, the Su27 isnt "following the missile straight in", its following its set course.