Mortgage loan and savings bonds question?

I was pre approved for an FHA loan, found a house, put an offer in and got the house and am now going through the long process before closing. One thing that has been a huge unexpected pain is my savings bonds that I cashed in before getting pre approved. I had the bonds since birth from my grandmother. The bonds were all in my mothers name. She cashed them in for me at her bank, then transferred the money to my saving account. My lender apparently doesn't like this. I thought the extra $4,000 would help with down payment and pre approval but they are turning into a huge pain. I've been called by the bank 5 times asking about them. I had to bring in proof the money transferred to my account was from them etc. Why is it such a huge deal? I could have won the lotto, received a gift of money, inheritance I don't why it is such a huge deal.