Probably still UT hun, I would go ahead and push A times more. Most 6 month olds are nearing a 3hr A time, I just thought we'd start with 2.5hr and see how it goes
40 min naps are very typical UT behaviour. What's happening is what we call a UT/OT loop. So she is UT for the first nap, thus takes a short 40/45min nap, but because it was not restorative, is then OT for the next nap, and thus takes a 30min OT nap - does that make sense? Typically 40/45min naps are indicative of UT and 30min naps of OT.
You'll probably need to ride out the rest of the day, but tomorrow I'd start fresh and go ahead and push to 2.45hr A time and see what that does.