In Trello, every comment needs to be assigned to a member. However, Placker not always has the authorization of every board member to make comments in their names.
In the following example, a member of the board (let's call her "Someone else") commented in Board 1 and the comment shows up correctly. However, that person doesn't have a Placker account, therefore hasn't authorized Placker to publish in her name in Board 2.
In this case, the comment will be assigned to the member who imported the board into Placker, as in the screenshot below, with a remark showing the member who actually added the comment.
Assigning the comment to the correct user
To solve this, you can ask your Trello team members to create an account in Placker and authorise Placker. Then Placker will start to create comments in their name. Even if members are not a full member of the Placker subscription.
Assigning the comment to a "neutral" user
If the previous step doesn't work for you, an alternative can be to create a dummy account and call it something like "Placker bot". Then, add it to the board and set the sync to this user at the board view / Click the board title / Members / Edit / Set sync right to the Placker bot: