Write to support@getpalmares.com and you will get an answer from the person who built the app. If a document of yours came out wrong, say what kind it is and I will fix the reading for that shape of paperwork.
Every value is editable before it is filed, and every entry stays editable afterwards. Nothing is written to your record until you confirm it. If a whole class of document reads badly, tell me what it is: faded thermal slips, stamped service books, dealer summary tables and continental number formats are all things I test against directly.
Open Settings inside the app and look at the Backup section. It reports what iCloud is actually doing, including refusals. Both devices need to be signed into the same iCloud account with iCloud Drive enabled. If it says the account is not signed in or storage is full, that is the cause.
Documents are read on your device. When a page defeats that, the app offers to send it for a closer read, and each one uses a credit. You get an allowance to begin with, more can be bought at €4.99 for 250, and the feature can be switched off entirely in Settings. Your records never depend on it.
Open Settings inside the app. Purchases restore automatically on launch through your Apple ID, and if a purchase does not appear, make sure you are signed into the same Apple ID that bought it. If it still does not, write to me with the date of purchase and I will sort it out.
No. Palmarès is bought once. Your records will never be held behind a recurring payment.
Yes. The dossier export produces a single PDF with the timeline, the odometer series and every scan behind it. It is meant to be handed to a buyer, an insurer or a workshop, and it is yours to keep whatever happens to the app.
Tell me what you were doing when it happened and what kind of document was involved. Bug reports of that shape get fixed quickly. There is no analytics in the app, so what you tell me is genuinely all I have to go on.