I'm having the same issue and it's driving me nuts.
With the first firmware you could do this but the noise would ramp up and oscillation would occur. Now with the new firmware the noise issue is gone but you simply cannot hit the record/dub button fast to record those short loops. The response time on that button has been decreased dramatically.
I just put in a ticket to see if this can be addressed but I see your post it from several months ago so I'm not too hopeful