A preferred return is a priority claim on cash that gets distributed. It sets an order of payment, so LP capital receives up to 8 percent per year on its contributed capital before the sponsor participates in the split above it. It's not a guarantee, not interest, and nobody owes it to you if the property doesn't produce cash. Loose market usage often calls it a "guaranteed 8" or "our 8 percent", which is where the confusion comes from.
The three modifiers do separate jobs. Cumulative versus non-cumulative decides whether an unpaid pref accrues as a balance owed to you later. Compounding versus non-compounding decides whether the unpaid balance itself earns the pref rate. Non-cumulative and non-compounding together means each year stands alone, and a year of no cash is simply a year of no pref, as ledger says.
One more thing worth finding in that same section: whether your original capital comes back to you before the sponsor's promote, or alongside it. A deal can pay a healthy pref and still hand the sponsor a share of proceeds while LPs are short on return of capital, depending on how the waterfall is ordered. Read the sale-proceeds paragraph, not just the operating-cash paragraph. They're often written differently, and the sale is where most of the money in these deals actually shows up. If the language is ambiguous, that's a question for a securities attorney reading the document for you rather than a forum.