Layout Developer 12.1.1.0 now allows the use of custom kerning tables with OpenType shaping. As with inline kerning, applying a kern inside a word will cause that word to be split into chunks.

To avoid any regressions or changes to output, a new property for fStyle has been created. fStyle.openTypeUseCustomKerning is a Boolean which tells the formatting process to apply custom kerning tables before word shaping when OpenType is turned on. If you are intending to use custom kerning with OpenType, set fStyle.openTypeUseCustomKerning = true.

As mentioned before, custom kerning tables are applied to characters, so be sure to apply kerning between the characters which are in the content stream rather than what you think the character is after OpenType shaping.