The moment a person's name and the mention of debt is voiced in the same message, that will commit a privacy violation under FDCPA. Right now it's just borderline. Not that PRA is afraid to break laws, but as seen across the industry, obeying privacy regs serves to keep the collector mysterious. PRA hopes you'll crack at some point and return the call.
The long pregnant pauses before a message are unusual, but not too surprising if the calls are computer controlled. Total dud messages should be considered abandoned calls, where TCPA should apply. Document calls and save recordings, silence and all.