Q.What Is Causing My Cucumbers To Grow Like This?
This plant had been producing normal cucumbers but now they are growing like this

Certified GKH Gardening Expert
Cucumbers that develop this kind of mottled skin, stunted shape, and odd curvature can be a sign of mosaic virus, a disease spread primarily by aphids or contaminated tools. Infected plants often produce a few misshapen fruits before declining further. The discoloration—especially the pale patches and rough, speckled texture—along with the curled ends, point to a viral cause rather than a nutrient or watering issue. If this is the case, there’s unfortunately no treatment. Affected plants should be removed and disposed of—not composted—to prevent further spread. Keeping weeds down, rotating crops, and planting resistant varieties next season are all smart steps. Insect control, especially for aphids, is critical. Even if the plants still seem vigorous, it’s best not to let the infection linger in the garden.
https://www.gardeningknowhow.com/edible/vegetables/cucumber/cucumber-mosaic-virus.htm
This collection of articles will offer more information on cucumbers:

