Why would altimeters split on a jet

Cabin Pressurization  leak bubbling outside the airplane.

Static leak allows cabin pressure in.

Ports not flat to airflow.

Shape and condition of sealant around ports

 

Bug in line.

SSDC curve different right to left.

Static lines not crossed.

Dent fwd of Static ports.

One ADC gets crazy when it gets cold.

Paint stripe edges on a fast airplane.

Turn buble mounted slightly crooked, causes pilots to trim the aircraft out of level. Affects static ports.