Weird LUT behaviour

[MinatoXVI]

Hi, for my thesis i generated many FINN variants of the same net for Google Speech Commands V2 classification.
The Architecture is a small version of MobileNetV1.
The target is a ZCU104.

I analyzed different (network wise) bit widths for different throughput targets.
As you can see in the image, the LUT utilization is a little weird for 3 bit weights. (Taken from the Vivado synthesis report)

Does someone know why this is happening?