The babinski sign can be temporary, apparently.
I have downgoing plantars on my right foot. On my left foot I don’t seem to have a response. However, the neurologist tried my left foot a few times, the last one of which I just stretched my toes as my foot was getting a bit tense, just as he did it - it looked like the Babinski sign and my neurologist nodded to himself when it happened, so I suspect it was put down as the Babinski response! However I know it was me doing a voluntary movement!