May be related to MC45046, may be duplicate of MC73139.

When over the height limit (y > 256), and the player presses F5 to view themselves, under certain circumstances the player cannot be seen. When the camera is moved, the player may disappear when the camera is positioned at certain vertical angles.

Press F3 to display the debugging information. Note the vertical angle (the second angle that is displayed) on the "Facing" line. 90 degrees is straight up.
Press F5 to view the player from the front. (The bug also manifests itself when viewed from behind but the behaviour is different).

Teleport to the given y coordinate.

At y=256, the player is rendered normally.
At y=258, the player disappears when the vertical angle is between 25.3 and 43.8 degrees.
At y=260, the player disappears when the vertical angle is between 18.0 and 52.7 degrees.
At y=262, the player disappears when the vertical angle is between 0.9 and 60.8 degrees, and also over 64.2 degrees.
At y=263, the player disappears when the vertical angle is over -5.6 degrees.

As the height increases from this point, the cone of player visibility steadily shrinks.

At y=360, the player disappears when the vertical angle is over -47.2 degrees.
At y=512, the player disappears when the vertical angle is over -49.9 degrees.
At y=522, the player disappears when the vertical angle is under -89.8 degrees, and over -50.1 degrees. This is the lowest height where the player is also not seen from above (-90 degrees).

From this point, the lower cone of invisibility grows rapidly until the player is no longer visible.

At y=540, the player disappears when the vertical angle is under -71.9 degrees, and over -50.3 degrees.
At y=601, the player disappears when the vertical angle is under -52.5 degrees, and over -50.4 degrees. This is the highest integer y coordinate where the player model renders at all.
At y=602 and higher, the player disappears at all viewing angles.