Unfortunately the genealogy on Wikitree for this is not reliable.
Alice Lyons is shown as your shared grandmother because of the assertion in Wikitree that Elizabeth Lyons, Alice's daughter, is the mother of John Wydeville.
However, more reputable sites (such as the late Leo Van de Pas's Genealogics and Cawley's Medieval Lands) show that John Wydeville was the son of Richard de Wydeville by a first wife (name unknown) and not by his second wife Elizabeth Lyon. As these sites show, John Wydeville (who married his second wife before 1379) was born in the early 1340s (not in 1370, as asserted on Wikitree), and thus cannot be the daughter of Elizabeth Lyons, whose first husband Nicholas Chetwode died about 1369.
More generally, there is a lot of junk medieval genealogy still on Wikitree (despite valiant efforts by Wikitree projects to clean it up), and thus medieval relationships found on the Relationship Finder cannot be trusted.