Hi Lindsey,
Generally speaking, the SW is not allowed to be routed under the IC. GND trace is ok. You can also follow the layout example of TPS56339EVM . This layout is better than the TPS54308.
Hi,
Over voltage on the input side is highly suspected. Please try to measure the voltage spike on the input cap under different conditions.
Schematic of TPS54302 looks ok. On the layout, the 100nF MLCC cap at the input side should be very close to IC…