Images not received in group chat, duplicate "Message-ID: <xxx>"s

- Sender Operating System:
- iOS, freshly installed last week

- Receiver Operating System:
- Desktop Linux v2.43.0
- Android v2.43.0
- Android v2.46.0 (Arcane)

## Expected behavior

In a group chat 5 images should be sent and received completely.

## Actual behavior

A group chat with >20 persons, 8 persons didn't received the 5 images. The others didn't say anything.
Only the first and the last image was received. Images in the middle are missing.

## Analysis

Thunderbird shows all e-mails with all images.

Maybe the Message-IDs are the problem. Shouldn't they be the different?
Additionally -file names- are the same but the -images itself- are different.
```
Message-Id | In-Reply-To | attachment file name | received in Delta?
11111111 | 55555555 | aa.jpg | yes
22222222 | 55555555 | |
11111111 | 11111111 | bb.jpg | no
33333333 | 11111111 | |
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | cc.jpg | no
11111111 | 11111111 | dd.jpg | no
44444444 | 11111111 | ee.jpg | yes
```
(IDs and filenames uniquely replaced in this table)

According to the sender 5 images should be visible. 10 different images are on the server.

Maybe it's connected to "send multiple images" dialog.