Apple Pencil Pro squeeze gesture stops working inside Notes after screen protector swap

The thicker tempered glass increases the dielectric gap between your fingers and the Pencil Pro’s squeeze electrodes (located under the matte cap), attenuating the ~100–300 kHz near-field coupling the sensor relies on. Hover works because it uses the iPad’s display-side mutual-capacitance grid (stronger field, larger RX/TX area), whereas squeeze is a self-capacitance measurement on the accessory itself—far more sensitive to added series capacitance. CLI check: Pair Pencil → xcrun developerctl device log --predicate 'subsystem == "com.apple.pencil"' while squeezing; look for SqueezeGestureRecognizer confidence scores dropping below 0.6. Recovery: Remove protector → test baseline → if restored, the glass exceeds the ~0.35 mm effective thickness budget for reliable squeeze detection; switch to a ≤0.3 mm PET/film protector or use the “Squeeze Sensitivity: Firm” setting (Settings → Apple Pencil → Squeeze) to raise the detection threshold.

Squeeze detection requires a minimum ~0.8 N normal force distributed across the flat bezel; a thick, rigid glass protector can act as a stiff shim that redirects finger pressure toward the curved barrel instead of the flat electrode pads, especially if the protector overhangs the Pencil’s flat edge by >0.2 mm. CLI check: sudo powermetrics --samplers smc -i 100 -n 1 | grep -i "pencil\|stylus" while squeezing to verify the SqueezeForce telemetry channel reports >800 mN at miss events. Recovery: Apply a 0.1 mm conductive copper tape shim only on the flat bezel under the protector (aligned with the two rectangular squeeze electrodes) to restore the force path; alternatively, enable AssistiveTouch → Custom Gesture → “Squeeze” as a software fallback while testing thinner protectors (ESR Paper-Feel 0.15 mm or Apple’s own Polyurethane sleeve).