I installed the pimoroni NVMe Base + 250GB SSD package on my pi 5, with the latest update of unmodified raspberry pi OS I get the following dmesg errors repeatedly:
[14103.810309] pcieport 0000:00:00.0: AER: Corrected error received: 0000:00:00.0
[14103.810322] pcieport 0000:00:00.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Transmitter ID)
[14103.810325] pcieport 0000:00:00.0: device [14e4:2712] error status/mask=00001000/00002000
[14103.810328] pcieport 0000:00:00.0: [12] Timeout