No. This is the Dokany Device object for all mounted vaults. For more info about devices and device object, have a look at the Microsoft documentation.
My thoughts are, that you can’t find a file in quarantine, since the given path is not a file system path and therefore the referenced object not a file.
User @linkingpin also mentioned a Windows 10 Defender message, see First Beta of Cryptomator 1.5.0 - #25 by linkingpin. A reboot solved this problem. Please report back if this issue persists, then we need to discuss this with the dokany developers.