Crash on Android with Qt NFC

When you move an Android app using Qt Nfc to the background and start it again by using the icon in the app launcher there is a crash with the following logentry: JNI DETECTED ERROR IN APPLICATION: GetMethodID received NULL jclass in call to GetMethodID.

This call comes from qnearfieldtarget_android.cpp
-> void NearFieldTarget::updateTechList()
-> tag.callObjectMethod("getTechList", "()[Ljava/lang/String;");