Setting "Type=Fixed" for an icon directory in index.theme prevents the icon from being scaled, or even used when a slightly larger size is requested (at least for Gtk applications). See https://bugs.kde.org/show_bug.cgi?id=355204 for an example of this.

It's particularly silly for SVG icons (which should be "Type=Scalable"), but even PNG icons should almost certainly be using the Threshold type.

Or am I missing something?

i read the bug report. thanks for feedback