Check the playback queue and try switching tracks using the Previous/Next buttons.
Actual result:
Only one audio track from the sendRichMessage is visually shown in the player. The other tracks are not displayed in the queue.
However, the other tracks seem to be present internally, because they can still be reached using the player navigation buttons.
There is also an ordering/navigation issue. Starting from the first track, pressing Previous switches to the second track, pressing Previous again switches to the third track, etc.
In other words, the navigation works like this:
Track 1 → Previous → Track 2 → Previous → Track 3
This issue can be reproduced in both Telegram for iOS and Telegram Desktop.
Expected result:
All audio tracks contained in the same sendRichMessage should be displayed in the audio player's visible queue, in the same order as they appear in the rich message.