I think I'm over (or under?) thinking this CTR and confusing myself, so I hope someone can set me straight!
Customer A is a joint owner on 2 accounts. She makes a $24,300 cash deposit to account #1 which is joint with customer B and customer C. She also makes a $1300 cash deposit to account #2 which is joint with customer D. So we have a multiple Part 1 CTR: $25,600 for customer A; $24,300 for customers B and C. My question is, would customer D be included on the CTR, since the only cash benefit she saw was the $1300?

Yes. Review the CTR FAQs found here: https://www.fincen.gov/frequently-asked-questions-regarding-fincen-currency-transaction-report-ctr . There is one that addresses this scneario (I can't remember which one and didn't have time to look it up)

I did read through the FAQs - must have missed this scenario. I'll read through them again. Thanks.

All persons benefiting from the cash deposits with their information would be included on the CTR as well as the person conducting the transactions. In the case of the conductor, the box would be marked "conducted on own behalf". All the rest would have the box marked "Benefited from the transactions".

Here is a similar thread: https://www.bankersonline.com/forum/ubbthreads.php/topics/2123043/ctr-question

Look at question #17 of the FAQs.

Thank you so much - I was definitely "under-thinking" on this one!