Yeah, Seasonic are one of the most consistently rated PSU suppliers and have been for years. You may just have had a unit with an issue which is rare but a real pain if it happens.
I'd check the plug, check the power cable and maybe try a different socket if possible. It might have been a power spike or something that's tripped the fuse in the PSU but that's as much as i know apart from check the PSU cables look ok and were connected solidly.
I'd expect an unhappy or overheating modern PSU to power down rather than go pop so i don't think the positioning was a problem.
I'd check the plug, check the power cable and maybe try a different socket if possible. It might have been a power spike or something that's tripped the fuse in the PSU but that's as much as i know apart from check the PSU cables look ok and were connected solidly.
I'd expect an unhappy or overheating modern PSU to power down rather than go pop so i don't think the positioning was a problem.