Looking at the variation in 1 Cor 3:5 I notice that NA28 lists P46 in support of the first τις as P46vid (from videtur), that is, it is the 'apparent reading, but not certain'.
So how much of τις should be visible in order to warrant this citation?
The image and transcription are actually very clear: There is not a single trace left of any of the letters of τις.
However, the second τις in the parallel question in 1 Cor 3:5 is there very clearly later in the final line. So on the assumption that the scribe of P46 was just as consistent as everybody else who copied this verse, it is not unreasonable to assume that P46 had at one stage τις ουν at the place where we now only have a gap. Still, it seems to me that this is pushing the normal use of 'vid' somehow.