There appear to be some answers about that error code here: hardware - What causes this? pcieport 0000:00:03.0: PCIe Bus Error: AER / Bad TLP - Unix & Linux Stack Exchange
It appears the software is detecting occasional errors at the hardware (“data link”) layer/level. It is hard to say what might be causing the error. For example, it could be caused by something like a power line running too close to one of your motherboard’s chips in your PC case, or the interference could even be coming from something external like a microwave oven or that giant unshielded nuclear reactor floating over our heads. 
Probably not since it reports “severity=Correctable”. However, it might be degrading your system’s performance.
There are limits set for how much disk space the logs can consume. When the limit is exceeded, the oldest logs are deleted. It would contribute to the “wear” on your disk, however, so I’d probably try to silence the messages with the pci=noaer setting that was mentioned in one of the comments in that StackExchange link.