Nope, just money grubbing local governments in action.

I experience something similar, but not nearly as drastic in VB in the 2000s. I had several years where my taxed property value jumped 25% (each year). After they realized they had over-estimated the property value, they decreased the assessment on the house, but increased the assessment on the land to exactly make up for the house decrease. Bastages! Eventually they got settled into a gradual increase which is what they use today.