Currently, the behavior of typing "@" in a post on Dynamics 365 is different between desktop and mobile.

 - Desktop : Enter "@" to display user entities, "#" to display records.

 - Mobile app : Enter "@" to display the record.

This behavior is confusing to users who use both desktop and mobile.

It is possible to make the behavior the same by enabling the rich text feature in the environment.

However, we may not want to enable the rich text feature for operational reasons.

It is more efficient to use Dynamics 365 if the default mentions behavior is the same between desktop and mobile.