Eu encontrei a razão pela qual isso aconteceu.
Para todos que podem ter o mesmo problema.
Eu tinha um plugin followwing instalado ACCPC
Plugin description
This plugin implements code completion for custom PHP classes in Notepad++. Keep an overview over your classes' attributes & methods in a nice popup!
A popup window appears after typing the "->" or "::" behind a class or an instantiated object variable which displays all attributes and methods of it's class. As soon as the popup appears you can type in the name of the method or attribute you are looking for and the plugin will select it in the list automatically. Hitting [return] or double clicking the entry will insert the name of the property to your script. Additionally, there is a list with all classes and their properties in a dockable window. Double clicking this entries opens their file & jumps right to the declaration. The list offers a quick search function also.
Author: Stanislav Eckert
Source: https://sourceforge.net/p/accpc/code/HEAD/tree/
Homepage: https://sourceforge.net/projects/accpc/
Latest update: 16.04.2014 (v1.3)
- Class constants and static attributes / methods can now be accessed by the "::" operator and are not visible in the popup for
"->"
operator anymore
Como você pode ver, a atualização fez alguns com o pressionamento de tecla que estou usando. Agora eu não tenho certeza se essa atualização foi o motivo, mas desde que eu desinstalei este plugin, ele funciona.