I've had similar issues with microSD in a variety of adapters. I think the core issue is most microSD cards just aren't built, in terms of thermals, for sustained writes. In most devices they're either read-heavy loads or burst-y writes. When you stick them in a warm laptop and do a lot of writes they overheat and start throwing errors.
replyFor many cards their drive controller might advertise and support higher UHS speeds the Flash memory is likely the cheapest silicon that can just barely pass acceptance tests. When I encounter cards that fail sustained writes I've had good luck using pv's (pipe viewer) rate limit. I stick it between dd invocations. This has worked well when writing OS images for Raspberry Pis onto cheap microSD cards. They're fine in the Pis but would fail trying to write OS images.
I've read the same, but for me, a newly-formatted microSD will overheat as soon as it's plugged into the MBP. The OS may be reading/writing something to cause that, but it's automated as part of the mounting process from what I've seen.
replyYou can try 'sudo mdutil -i off /Volumes/microSDCardName' which will disable Spotlight indexing on it. While a Spotlight index of an empty disk shouldn't cause overheating...there's bugs somewhere in the chain. To say nothing of quality issues on the cards themselves. I often use an app called Disk Arbitrator[0] to mount disks read-only or block automounts when I'm dealing with SD cards because of overheating issues.
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