Freedom of Movement RAW is a mess, and we don't know what it stops exactly. Relevant 3.5e question (but applicable to Pathfinder 1e as far as I know): What Are Freedom of Movement's Limits?
Moreover, maneuvers do not exist in regular Pathfinder 1e, and it's understandable that a core PF spell makes no special note about them.
The Shadow Pin maneuver is a really good counter; it stops melee characters from charging and getting near in general, and it stops recurring NPCs from teleporting away. No wonder one of my players took it.
The Freedom of Movement spell is meant to counter movement-blocking effects, but it only explicitly mentions making the recipient immune to mundane and magic impediments (emphasis mine):
This spell enables you or a creature you touch to move [...] normally for the duration of the spell, even under the influence of magic that usually impedes movement
Food for thought: It's magic, not "spells". Is "supernatural" magical enough to be included, given that it goes away in an antimagic field?
Does Shadow Pin bypass Freedom of Movement effects, or is it stopped by the spell?
(Since Freedom of Movement allows moving normally but says nothing about special movement forms such as teleportation, is the answer different for the teleportation part?)