Why an SD-card saved app uses phone memory
Link2SD only moves the app itself to your device's SDCard. App data still go to internal storage (/data/&lt;package_name&gt;). For every app you install, the Android system automatically creates this directory – and I don't know of any app that doesn't put at least a few files here.

For details, please take a look at the app2sd tag-wiki. It not only explains the different App2SD approaches taken (including Link2SD), but in "Extended Methods" also holds hints for a possible solution to your problem (S2E).