I overheard this yesterday.

Problem:
The adverb “back” in “report back” is redundant.

Explanation:
The verb “report” comes from the Latin verb “reportare”, which means to carry back.

So the meaning of “report back” would be to carry back back.

Because the “re” in “report” means back, one could argue that those who “report back” would never reach their intended audience.

For fun, I searched Google for the expression “report back” (with the quotation marks, to avoid variations) and got about 3,740,000 matches.

This is depressing.

Solution:
“They dotted-line report to Becky.”