I'd think stress is likely the culprit. Either the soil is the wrong kind, or using the wrong nutes or additives, or too hot, too humid, soil too wet, salt build-up, too much of something, not enough of another, lights too close, lights too far away, wrong light spectrum...or none or all of the above.

You'll need to copy-n-paste the troubleshooting form here, and answer as many of the applicable questions as you can. The more info you provide, the better.

After reveg, my ladies will throw-out single finger leaves for a week or two, but once they recover from the stress of switching from 12/12 to 18/6, and the root trim, and downsizing their pot...normal vegetative growth continues. I call it the WTF phase. (the plant saying "what the f just happened...?")

It's not really normal for clones, though.
If you fill out the troubleshooting form, I'm sure we can narrow the focus. :thumbsup: