There's the rub.
UEFA started an investigation, they didn't conclude that investigation, they relied on hacked emails and press reports taken out of context, they didn't pass information to City and therefore didn't allow City to present any evidence or rebuttal, they kicked the issue upstairs to avoid missing the statute limitations, they only presented a "scope" document because they couldn't provide an investigation report as the investigation wasn't complete, they're questioning the published accounts of major companies, they've exceeded their own powers by reopening a case that was settled in full, they've exceeded their own power by investigating beyond the current FFP reporting period, they've exceeded their own powers by passing an unfinished investigation to the adjudicatory chamber, they have seemingly deliberately leaked data on multiple occasions including after City had asked them to cease doing so.