The tips of growing vines should be vertical and point almost straight upward, particularly in the morning. During the day, in high-temperature conditions, they might move to a slight angle, but should still be mostly upright.
When a growing tip is bent over sideways, as this one is, it is an indicator of a calcium deficiency. It can also be an expression of dry soils and not enough water. Since the plant needs to absorb calcium from the roots each 24-hour photoperiod, which is then transferred through the xylem directly to the new growth, saying that a bent tip is the result of not enough water is just a different way of saying that it doesn’t have enough calcium.
Observing the growing tips on cucumber vines is an easy assessment that can indicate whether the plant has enough energy to fill multiple fruit on each node and continue setting new fruit.