T is position 5 on a top 10 Over Valued list in the website
Extreme Value Stocks
Seems like a serious site.
T is not even mentioned. Anyway, undervalued or overvalued is decided by the market on each transaction. The buyer thinks it is undervalued and the seller thinks it is overvalued.
For the most part, you are correct. However, there are cases when the seller needs the funds, and therefore, obligated to sell while he reamians bullish.