Why does the Torah say that the spies came to the Valley of Eshkol when it was not yet called by that name?
(13,23) “They came to the Valley of Eshkol (נחל אשכל) and they cut a branch with a cluster of grapes…They called that place the Valley of Eshkol (נחל אשכול) because of the cluster which the children of Yisrael cut from there.”
The question which needs to be asked here is how could the Torah say that they came to the Valley of Eshkol when it was not yet called by that name?
We can answer that the valley had in fact already been named a long time before after a man named Eshkol, like the name of one of the friends of Avrohom - Aner, Eshkol (אשכל without a vav) and Mamre.
Now, Chazal taught in the gemora Succah that the words בסכת בסכת בסכות signify four, and so too do the words קרנת קרנת קרנות. Because even though we pronounce these words as if they were written with a 'vav' and are thus plural, only when it actually has a 'vav' does it signify the plural but without a 'vav' it signifies only one. (And it seems to me that actually there used to be a difference in pronounciation between the two spellings).
Here too, we can explain that that the place had been called נחל אשכל without a 'vav' after a man named Eshkol, but when they cut the cluster of grapes the place became called נחל אשכול with a 'vav' to allude to the two reasons why it was named thus - for the man and for the cluster. Therefore the Torah writes “and they came to נחל אשכל” without a 'vav', and afterwards it writes “they called that place נחל אשכול” with a 'vav'.
The posukim in parshas Vayishlach (Bereishis 34:17) - “and Ya’akov journeyed to Succos (סכתה) and built for himself a house, and for his cattle he made booths (סכת). Therefore, he called the name of the place Succos (סכות)” - can be similarly explained. Because here too we have the same difficulty that we had above, and so we must explain like before that therefore it writes that “Ya'akov journeyed סכתה” without a 'vav', and then wrote that “therefore he called the name of the place סכות” with a 'vav', to allude to the two reasons for naming the place thus.