I take GaramondPremrPro for example.
The glyph of the / I / has: LB 35 and RB 26; the kerning added for the pair / II / is 9pt, so it is symmetrical: 35pt distance between the two serif close together at the bottom.
The glyph of the / E / has: LB 19 and RB 23. The pair / IE / has 9pt of kerning: in this case the two serif close together at the bottom are 54 pt apart.
The glyph of the / A / has: LB 4 and RB 1. The pair / AA / has 10pt of kerning, so that the two close serif below are only 15pt apart.
Are these different distances normal?
At least the couples / II / and / IE / shouldn't be equidistant?