Year range Heathcliff

Currently, Heathcliff has a year range of 1980-1984: https://www.imdb.com/title/tt0173556/reference/ 

However, as you can see, all episodes on IMDb are from 1980-1981.

TVmaze also says this series ran from 1980-1981: https://www.tvmaze.com/shows/46528/heathcliff 

So does epguides.com: https://epguides.com/Heathcliff/ 

Can a staffer look into this and fix the year range please?