[Yaffs] yaffs_VerifyCollectedBlock report error

Hi,
yaffs_VerifyCollectedBlock reported "Block xxx is in state 4 after gc,
should be erased".
State 4 means YAFFS_BLOCK_STATE_ALLOCATING, how would this happen?

My testing environment is linux 2.6.24.3:
|1. modprobe nandsim first_id_byte=0x20 second_id_byte=0xa2
third_id_byte=0x00 fourth_id_byte=0x15| - 64MiB, 2048 bytes page;
2. mount -t yaffs2 -o sync /dev/mtdblock0 /mnt/nand
3. Then I ran postmark under /mnt/nand.
The file size is between 512B and 10kB.
The file number is 2000.
The transactions is 100000.
There were totally 312MB read and 336MB written to flash.

Have anybody encountered the same question?

best wishes, shizheng