Translink is being rebranded to Clipper, which will be formally "introduced" to the public on June 16.
Old Translink branded reader for Caltrain. This reader should've been rebranded by now.
New Clipper branded reader for light rail, but not activated yet.
When VTA comes on line with Clipper, whoever's in charge needs to distinguish which reader belongs to which system at inter-modal transfer points. Other than being located on the VTA platform, there's no difference in appearance between the reader for VTA and Caltrain. Perhaps someone in a hurry, or don't know the station well, would tap his or her Translink/Clipper card at the wrong reader, which would result in overcharge (when a VTA rider mistakenly tap on the Caltrain rider) and/or citation.