Hello,
Since the 12th of April 2021 the emojis are not displayed over Incoming Webhook posts.
Here are few examples:
Before 12th of April:
After the 12th of April:
I wonder what else was changed that day
UPDATE: After a bit of troubleshooting I found that Microsoft added the need for ";" at the end of the emoji. After the semi-colon was added, the message appeared as it was before the 12th of April.