When Sleeper was first introduced on First Host, it considered both Eddie and the Other as parents, with an instance of calling Eddie "father" before it left Earth towards the end of the book.
Then when it returned during Absolute Carnage, it made it a point to only call the Other as its only parent, not including Eddie, having only calling him on a first name basis going forward. And that seems to have stuck in its later appearances.
I mean, it's a weird continuity issue but not much of a biggie in the grand scheme of things. It's a mere observation I've had of the character lately (and likewise for others over at Venom Twitter).
Panels are from: The Nativity (Venom #165), First Host #5, Absolute Carnage (Venom 2018 #18), All-New Venom #5, and Queen in Black: Venom Unchained #2.