Issue with ChaCha20

[Mem5]

Hi,
Trying to crack the sample ChaCha20 hash from the source code :

Code:

static const char *ST_PASS = "hashcat";
static const char *ST_HASH = "$chacha20$*0400000000000003*35*0200000000000001*3961626364656667*8a152c57a7a856a8";

Code:

hashcat -m 15400 cha.hash wdlist.txt

wdlist.txt contains 'hashcat'

Code:

Status...........: Exhausted
Hash.Name........: ChaCha20
Hash.Target......: $chacha20$*0400000000000003*35*0200000000000001*3961626364656667*8a152c57a7a856a8
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........:        0 H/s (0.00ms) @ Accel:128 Loops:1 Thr:1024 Vec:1
Speed.#*.........:        0 H/s
Recovered........: 0/1 (0.00%) Digests
Progress.........: 1/1 (100.00%)
Rejected.........: 1/1 (100.00%)
...

Why Rejected.........: 1/1 (100.00%) ?

Same result on hashcat v5.1.0 and beta 5.1.0+1394.
Same result with the hash from samlple page https://hashcat.net/wiki/doku.php?id=example_hashes

Thanks.