Strange parameters in datasheet of 74HC4046
Those are not typos.  You are not interpreting the specifications correctly. For the HIGH levels, the specification is giving the minimum value that is guaranteed to be recognized as a HIGH, e.g. 2.1 volts when Vcc = 3.0 volts. Any voltage higher than 2.1 will be recognized as a HIGH. The typical voltage, 1.7 volts, is the value that a typical device will recognize as a HIGH but it is not guaranteed.  Similarly, the maximum voltage that is guaranteed to be recognized as a LOW is 0.9 volts when Vcc = 3.0 volts. Any voltage lower than 0.9 volts will be recognized as a LOW. Typically, however, a value as high as 1.2 volts will be recognized as a LOW, but again this is not guaranteed. All of the other values in the specification should be interpreted in the same way. In general, maximum and minimum values are guaranteed, typical values are not.