I can’t find anything in campaign law that says personal loans based on personal assets as collateral need to be reported. These were not loans to the campaign and were not the responsibility of the campaign to pay back.
The last I read, they were waiting for the FEC to make a determination and if need be, they would file an amendment.
The issue is those loans don’t fit the narrative that Cruz has created for himself. Sneaking them by with “they may be legal and if not the report will be changed” doesn’t change that.
They were personal loans that Ted then loaned to his campaign.
They were supposed to be filed with the FEC because Ted loaned the money to his campaign and his campaign repaid at least part of it.
They have to be reported because someone could, hypothetically, arrange such a loan with a bank, give it to his campaign, and then someone else could pay it back or the bank could forgive it for political favors.
I am not saying this happened. I am saying this is the reason it is supposed to be reported to the FEC.
May not answer your campaign law search but it gives a detail of the Cruz loan situation
http://www.npr.org/2016/01/14/463093708/the-ted-cruz-goldman-sachs-loan-explained