Basically, the crime alleged was violating a NY election law saying that you can't try to influence an election through "unlawful means". They provided a sampling of said unlawful means: violating federal campaign contribution limits, falsifying other business records, and violating state tax laws about how the reimbursement to Cohen was handled. The jurors didn't have to unanimously agree about which of those things they think he actually did.
The reasons to not charge him for those separately would seem to be respectively: 1. that's the feds job, 2. statute of limitations expired for the non-felony falsifications during his presidency when he couldn't be charged with anything, and 3. Cohen directly committed the tax crime so all Trump's guilty of is conspiracy to commit a really niche bit of tax misrepresentation that didn't actually cost anything.
The unambiguous bit is that he definitely falsified business records, and so the squabble is over whether he's guilty of a misdemeanor or a felony. It was apparently persuasive to the jury that he did the felony version.