abreviations in ap. crit for 451b

I do not understand the following abbreviations: γνῶσις secl. Bekker, sed latet fort. corruptio major. Probably: Bekker cut off gnosis, but greater corruption lies probably hidden. If my understanding is correct, then is it better to include or exclude gnosis?

actually, this gnosis does not fit into the sentence, so probably it is a scribal error.

secl. = secludit or seclusit, i.e. Bekker square-bracketed it as intrusive, not part of the authentic text; but he thought the corruption possibly went deeper. It’s hardly to be dismissed as a scribal error.