The adaptors slow things down a bit which is what causes the various compatibility issues - if you use a full size SD whenever there is a full size SD slot and a microSD in a microSD slot things are fine.
When you start using adaptors to use a microSD in an SD or vice versa things start to get complicated.
Native Komputerbay 128GB SDXC 90MB/s full size SD card in full size slot in Kingston USB3 reader:
Code:
Sequential Read : 89.317 MB/s
Sequential Write : 38.927 MB/s
Random Read 512KB : 61.762 MB/s
Random Write 512KB : 28.826 MB/s
Random Read 4KB (QD=1) : 6.529 MB/s [ 1593.9 IOPS]
Random Write 4KB (QD=1) : 1.051 MB/s [ 256.7 IOPS]
Random Read 4KB (QD=32) : 9.219 MB/s [ 2250.8 IOPS]
Random Write 4KB (QD=32) : 1.502 MB/s [ 366.7 IOPS]
Same card in same Kingston USB reader in microSD to full size SD adaptor:
Code:
Sequential Read : 23.657 MB/s
Sequential Write : 21.551 MB/s
Random Read 512KB : 20.895 MB/s
Random Write 512KB : 18.216 MB/s
Random Read 4KB (QD=1) : 5.369 MB/s [ 1310.8 IOPS]
Random Write 4KB (QD=1) : 0.945 MB/s [ 230.8 IOPS]
Random Read 4KB (QD=32) : 7.033 MB/s [ 1717.0 IOPS]
Random Write 4KB (QD=32) : 1.291 MB/s [ 315.1 IOPS]
It's the same card in the same reader, just in an adaptor, and you can see that the throughput of various IO patterns drops across the board.
This is why you can start to get glitches as the card just can't keep up - basically the adaptors can make the fastest cards run as slow as a card from years ago
The above example actually worked but your milage will vary as cheap adaptors with microSD cards will slow them down and they're not usually the quickest to start off with!