As of 2022, TV Tropes's less specific analogue, "Sequelitis", may apply here.

A film series can include multiple overlapping sagas/stories which ought to be recognized as separate, due to creators getting replaced or ignored over time, even if the series allegedly occurs in a single "universe." For example, regarding just the five movies added to this list through 2017, eleven stories have been created separately. Three overlapping stories upon the release of ALIEN 3 in 1992 ...

ALIEN

ALIEN + ALIENS

ALIEN + ALIENS + ALIEN 3

... and eight overlapping stories upon the release of THE LAST JEDI in 2017 ...

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + THE FORCE AWAKENS

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + ROGUE ONE

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + THE LAST JEDI

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + THE FORCE AWAKENS + ROGUE ONE

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + THE FORCE AWAKENS + THE LAST JEDI

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + ROGUE ONE + THE LAST JEDI

A NEW HOPE + THE EMPIRE STRIKES BACK + RETURN OF THE JEDI + THE PHANTOM MENACE + ATTACK OF THE CLONES + REVENGE OF THE SITH + THE FORCE AWAKENS + ROGUE ONE + THE LAST JEDI

See, creators shouldn't be judged on the basis of story installments which they haven't clearly sanctioned. That's why I keep tabs on this stuff. For example, as of 1986, Ridley Scott and his associates are accountable for ALIEN alone. However, James Cameron and his associates are accountable for ALIEN and ALIENS in combination. Such is the burden of all artists who make fictional works that elaborate on others: to create not just good installments, but good overarching sagas.

Note that certain films, like ROGUE ONE, have more than one predecessor group. On the other hand, films like ALIEN 3 do not because they're insufficiently creatively linked to some previously-released chapter(s). Also, note that not every predecessor group is necessarily a continuous-chain predecessor group.