They were modelling a fluidized bed reactor. The issue was their understanding of what the signal meant, they wrote a rather lengthy report full of nonsensical

They were modelling a fluidized bed reactor. The issue was their understanding of what the signal meant, they wrote a rather lengthy report full of nonsensical recommendations on basis of not properly understanding what the input variable represented. edit: At least at my org we use multivariate a lot this is mostly primary metallurgy not pure chem eng though.