I am debugging a power amplifier circuit and trying several capacitors values to fine tune the design to meet the frequency response specifications. All the 0603 and 0805 ceramic capacitors are experiencing the following issue:
I measure the capacitor (this one for example) using this digital LCR meter which reads 360nF (typical value 390nF with 10% tolerance). When I hand-solder the capacitor, it reads 420nF in-circuit, and when I desolder the cap, it still reads 420nF. What caused this big increase in capacitance?!