mockserver wrongly transofrm binary body data when return response for forwarded request

[andrake16]

i configure mockserver to forward request
"httpForward": {
"host": "report.com",
"port": 15001,
"scheme": "HTTP"
}

in TRACE log i see that mockerver get byte sequence

2024-09-25 15:09:15 5.15.0 FINEST [id: 0xd0d31db3, L:/172.21.0.2:60920 - R:report.com:15001] RECEIVED(2048B)
mockServer-1 | |00000180| 30 80 06 09 2a 86 48 86 f7 0d 01 07 01 a0 80 04 |0� *�H��/��|
mockServer-1 | |00000190| 82 0e cc 3c 3f 78 6d 6c 20 76 65 72 73 69 6f 6e |��/<bki_r|

it is begin of body:
30 80 06 09 2a 86 48 86 f7 0d 01 07 02 a0 80 30
but then write in response another sequence
30 ef bf bd 06 09 2a ef bf bd 48 ef bf bd ef bf

mockServer-1 | 2024-09-25 15:09:15 5.15.0 FINEST [id: 0xe938e47d, L:/172.21.0.2:1080 - R:/172.21.0.1:36978] WRITE(4578B)
mockServer-1 | +-------------------------------------------------+
mockServer-1 | | 0 1 2 3 4 5 6 7 8 9 a b c d e f |
mockServer-1 | +--------+-------------------------------------------------+----------------+
mockServer-1 | |00000000| 30 ef bf bd 06 09 2a ef bf bd 48 ef bf bd ef bf |0.....*...H.....|
mockServer-1 | |00000010| bd 0d 01 07 02 ef bf bd ef bf bd 30 ef bf bd 10 |�/��0�|
mockServer-1 | |00000020| ef bf bd 02 01 01 31 0e 30 0c 06 08 2a ef bf bd |�10
*�|
mockServer-1 | |00000030| 03 07 01 01 02 02 05 00 30 ef bf bd 06 09 2a ef |0� *�|
mockServer-1 | |00000040| bf bd 48 ef bf bd ef bf bd 0d 01 07 01 ef bf bd |��H��/�|
mockServer-1 | |00000050| ef bf bd 04 ef bf bd 0e ef bf bd 3c 3f 78 6d 6c |���<?xml|
mockServer-1 | |00000060| 20 76 65 72 73 69 6f 6e 3d 22 31 2e 30 22 20 65 | version="1.0" e|
mockServer-1 | |00000070| 6e 63 6f 64 69 6e 67 3d 22 55 54 46 2d 38 22 3f |ncoding="UTF-8"?|
mockServer-1 | |00000080| 3e 0a 3c 62 6b 69 5f 72 65 73 70 6f 6e 73 65 20 |>/<bki_response |

as i know character that cannot be encoded are replaced with EF BF BD in UTF-8

response headers that responsed my server report.com is
HTTP/1.1 200 OK
server: nginx
date: Wed, 25 Sep 2024 15:50:08 GMT
content-type: application/octet-stream; charset=UTF-8
transfer-encoding: chunked
x-powered-by: PHP/7.4.33
x-frame-options: SAMEORIGIN
x-content-type-options: nosniff
x-xss-protection: 1; mode=block
strict-transport-security: max-age=31536000; includeSubdomains;

yes i know that there is
content-type: application/octet-stream; charset=UTF-8
but why used utf-8 encoding for binary data? it is digital signature at the beginning of body may be or hash

as result i get wrongly rewrited bytes my mockserver(or netty)
why it not just rewrite it as is using binary bytes - without encoding?
is there a way to force mockserver to transfer original response(byte by byte) from server when forwarding?

5.15 latest
DOCKER

sorry for my english i hope my mindflow is recognizable))

[andrake16]

steps to reproduce:
just setup mockserver to forwarding to serverA who response as

then - send request to mockserver - and it will answer
30 EF BF BD 06 09 2A EF BF BD
instead of correct response which should be
30 80 06 09 2A 86