This may be due to a deficiency of boron.

2 4 D can cause the symptom of buggy whipping it does not need to be in your field but a neighbor field can cause the issue. It is also found in warm followed by cold in the spring growth period. The issue can occur from calcium deficiency often occurs together with boron.

1. These kind of symptoms occurs when too cold weather (below 4 Celsius) followed by sudden warm temperatures (above 25 Celsius)

2. The 2-4 D spray in your fields or nearby with drift may cause such a symptom.

but the 1 is more common reason

The symptom your are showing is called buggy whipping.

Concur that response to temperatures may be important.

Also calcium deficiency and 2 4 D phytotoxicity.