@Alexandre_Jodoin We are working through a wide range of hosts with support to get to the bottom of this situation. One of the commonalities ended up being deleted Installation Packages under Cortex XDR Administrative Console >> Endpoints >> Endpoint Management >> Agent Installations. I'm not saying this is the case for you but we did not know that someone was cleaning up these packages and wouldn't have though it would put the agent dead in the water. The agent is not smart enough to go out and get the latest version from the console if the previously sent version no longer exists.
A helpful command that we used is below. This prevented us from having to reinstall the agent in a number of situations.
We are working through some other scenarios so I will update this post accordingly in hopes to help out some other customers in our situation.