Kepner-Tregoe Problem Analysis says something changed in the production
line in India.

Either with the parts or with the personnel or with the procedure. It
is usually a person.
We had a problem here at work with a valve traceable to a supplier who
had an untrained summer student for about a month who did not get
trained on a small critical detail.

This is typical KT Problem Analysis, look for what changed on the the
Time Line for this radio production

Paul