Batch export unable to use channel names

I’m having a weird problem here, considering I’m doing what I always do. When I try to batch export some tracks I get a box saying “please change your naming scheme, as it does not provide unique names for the files.”

I’m only using the channel name, and to my knowledge that should definitely create unique names, because they are. Simple logic to humans, but not to Cubase this particular day. And I have a lot to export today. :frowning:

Any ideas what this could be?

I’m running 6.5.3 in 32bit on Windows 7 64bit.