Simulink array size changes along route

I'm getting this error in my model:

Error in port widths or dimensions. Output port 1 of 'Model/Selector' is a [126x1] matrix.

Component:Simulink | Category:Model error

Error in port widths or dimensions. Input port 1 of 'Model/Dot Product/Product' is a one dimensional vector with 1 elements.

It looks like a block that feeds into the block with the error is changing array size for no reason, does anyone know what could be causing this?

The image below shows it going from 64x3 to 126x3

Thank you!