attenuation with 1 mating sleeve :

green jacket fiber : -0.4 dB

blue jacket fiber N°1 : -0.5 dB
blue jacket fiber N°2 : -0.27 dB
blue jacket fiber N°3 : -0.13 dB
blue jacket fiber N°4 : -1.4 dB

we should try to polish at least the fiber 4 which seems faulty.