Been using TF card on 5A just fine until I switched to eMMC and I found similar file system corruption. It usually happens shortly after the system starts, such as when using apt update. The eMMC module works fine on Rock 5B. I also tried the latest kernel “5.10.160-rockchip-rk3588” with no luck.
[ 345.286190] blk_update_request: I/O error, dev mmcblk0, sector 14049280 op 0x1:(WRITE) flags 0x4800 phys_seg 32 prio class 0
[ 345.337889] EXT4-fs warning (device mmcblk0p1): ext4_end_bio:347: I/O error 10 writing to inode 266834 starting block 1756518)
[ 345.338064] Buffer I/O error on device mmcblk0p1, logical block 1752064
[ 345.338095] Buffer I/O error on device mmcblk0p1, logical block 1752065
[ 345.338101] Buffer I/O error on device mmcblk0p1, logical block 1752066
[ 345.338114] Buffer I/O error on device mmcblk0p1, logical block 1752067
[ 345.338126] Buffer I/O error on device mmcblk0p1, logical block 1752068
[ 345.338138] Buffer I/O error on device mmcblk0p1, logical block 1752069
[ 345.338149] Buffer I/O error on device mmcblk0p1, logical block 1752070
[ 345.338161] Buffer I/O error on device mmcblk0p1, logical block 1752071
[ 345.338174] Buffer I/O error on device mmcblk0p1, logical block 1752072
[ 345.338188] Buffer I/O error on device mmcblk0p1, logical block 1752073