It is stress, dropping a few leaves because of the cold more than likely. They don't like anything below 50 degrees depending on the specific plant, perhaps even 60 degrees. If it warms up, you should see new growth. I see you've been down around low 40's, so the weather is probably the culprit. I can't say for positive, but my "small" edulis have weathered low 40's in pots, so I suspect your large vine will recover. Good luck.

my incarnata died last year during the summer
i never found out what it was, but it must have been a virus or something like that.
the leaves wilted just like this one. it started in one spot, and went to the whole plant.
i had another one about 20ft away that never had a problem, actually, that one took off and got huge.
if it did get cold enough , and was wet for an extended period, it could be root-rot ?
that will make it look like it is not getting enough water, but thats just because it has no roots to absorb it.

We have decided to take these out and try something new. Will solarize the soil as suggested. Thanks for all the great feedback!