All forum types automatically transition to the standard Canvas Discussion within the imported course file. If a forum is graded, the forum grade will transition correctly. However, most other settings are lost.
Noting Forum settings
Go to the forum in Moodle.
Find the Administration block:
Click Edit settings.
Check the General settings and note if the Forum type is a Q&A forum. (These forums require a user to post before seeing replies).
Expand the Common Modules settings to see if the forum is a group discussion.