The lines in question:
https://github.com/Vazkii/Patchouli/blob/master/src/main/java/vazkii/patchouli/client/book/gui/GuiBook.java#L229
https://github.com/Vazkii/Patchouli/blob/master/src/main/java/vazkii/patchouli/client/book/gui/GuiBook.java#L232

Details:
At the current time, this calls the overload that accepts List<? extends IReorderingProcessor>, because, for whatever reason, the correct overload of the function, does not have a proper name, and so the obfuscated func_243308_b should be what is used instead.
This is important, because the overloads that accept a List<? extends IReorderingProcessor> rather then a List<ITextComponent> do not cause the forge tooltip events to fire.

Discovered this issue while trying to help MercuriusXeno debug why his custom tooltip rendering did not work within patchouli.