Update: Case description:
On ACS Call Information
Call #1 relates to ACS call that joined immediately after the calendar entry is created.
Call #2 relates to ACS after it is disconnected from Call #1 and rejoined again after a small time gap. The second one showed up in the MS Teams call, not the first one.
After internal finding it came out that the only difference is for the first call, the meeting link comes directly from API and for the second one, it was inputted manually in the UI And the issue was on some parts of UI code strips out the https://. So before joining the call, https:// was added to the meeting link.
For the call #1, the link comes directly from API call, https was not removed and while joining the meeting https was added again. So the meeting link will have one extra protocol identifier After fixing this is resolved.