A customer implemented a nRF52840 (QIAA package) and says the output power is about 10dB lower than expected. Having done multiple nRF52 designs with good results, I reviewed their schematic and layout and observed that it generally looks pretty good. The only obvious concern I found is that they do NOT have the VDDH pin connected. They are powering VDD with 3.3V and otherwise following the Normal Voltage mode with DC/DC (except that the Supply is only connected to VDD and VDDH is Not Connected). Could that cause the output power to be out of spec?
I've only reviewed their HW design, but they may also have a SW issue which has not yet been investigated.