With Canon Cameras, when shooting tethered using Canon EOS Utilities, it is necessary to turn on a feature in Canon Software to allow Capture One to effectively use the Hot Folder Feature.
Once the Camera has been connected to EOS Utilities please be sure to turn on the "Remote Shooting" feature within EOS Utilities.
This feature, after the first image is shot, will create a Sub Folder within your designated "Destination" folder. Be sure to establish this folder as the "Capture Folder" within Capture One and turn on the "Hot Folder" feature.
Why does this happen?
The Canon tethered process sends the file to the computer with a specific "name" that does not reflect the file name that you ultimately see. This temporary name is then changed to the final name once the entire image is transfered.
As Capture One tries to access the image the moment it sees it, prior to it finally being written, it is accessing a file which moments later does not exist (due to the name change) and therefore does not show up in the Capture Folder without a refresh. The "Remote Shooting" feature of Canon EOS utilities prevents this behavior and the file is sent from the camera as the same name you see.