Inherited property: exemptions end, and the record is usually stale
The exemptions died with the owner. The assessment probably has not been looked at in years.
Inheriting a house frequently produces a tax bill far larger than the one the family was used to, for reasons that have nothing to do with a reassessment.
The exemptions end
Senior homestead exemptions and the senior freeze are personal to the qualifying owner. On death they stop. If the deceased held the freeze for years, the property returns to its unfrozen assessed value — which can be a very large step in one year.
The general homestead exemption too
Unless an heir occupies the property as their principal residence, it does not continue.
The record is likely stale
A house held for decades by an older owner is often recorded in better condition than it is. Original kitchens and bathrooms, an old roof, dated mechanicals — the model assumes typical upkeep. This is frequently a strong condition argument, with photographs.
If you are selling
An arm's-length sale is the best possible evidence of value. If it sells well below the county's implied value, that supports an appeal for the year in question — worth doing even if you no longer own it, where the liability is yours.
Practical first step
Ask the assessor what exemptions were on the property and which have ended. That explains most of the increase before you consider anything else.