Looks like the SD card is faulty:
$ ~ f3write /Volumes/Untitled
Free space: 3.61 GB
Creating file 1.h2w ... OK!
Creating file 2.h2w ... OK!
Creating file 3.h2w ... OK!
Creating file 4.h2w ... OK!
Free space: 0.00 Byte
Average writing speed: 1.15 MB/s
$ ~ f3read /Volumes/Untitled
SECTORS ok/corrupted/changed/overwritten
Validating file 1.h2w ... 2097152/ 0/ 0/ 0
Validating file 2.h2w ... 2097152/ 0/ 0/ 0
Validating file 3.h2w ... 404848/ 0/ 0/ 0 - NOT fully
read due to "Resource busy"
Validating file 4.h2w ... 1275912/ 0/ 0/ 0
Assertion failed: (tot_size / SECTOR_SIZE == (tot_ok + tot_corrupted +
tot_changed + tot_overwritten)), function iterate_files, file f3read.c,
line 210.
[1] 15899 abort f3read /Volumes/Untitled
Dainele