A patch delivery device includes a bottom housing part, a delivery element for subcutaneous delivery of a liquid to a patient, an adhesive patch for attaching the bottom housing part to the skin of the patient, a capacitive sensor with an electrode configuration including a plurality of skin contact sensitive electrodes, and a release liner covering a patient-side adhesive layer of the adhesive patch prior to adhering to the patient's skin. The release liner includes an electrically conductive area extending over at least a portion of the electrode configuration of the capacitive sensor before being removed from the adhesive patch. Providing the release liner with a conductive area gives rise to a discernible change in capacitive response of the sensor electrodes upon release liner removal that enables sensing a removal of a release liner covering a patient-side adhesive layer prior to attachment to the skin of a patient.