New Oracle Reincation created

I have an Oracle 19c environment, where the primary has a standby and the standby has its own standby (Cascading DR). Somehow the standby's DR's incarnation changed to a new one. In the logs, I get this:

rfs (PID:1286351): A new recovery destination branch has been registered
 rfs (PID:1286351): Standby in the future of new recovery destination branch(resetlogs_id) 1177883943
 rfs (PID:1286351): Incomplete Recovery SCN:0x000000003b52f9a6
 rfs (PID:1286351): Resetlogs SCN:0x0000000039031be8
 rfs (PID:1286351): SBPS:0x0000000039031be5
 rfs (PID:1286351): Flashback database to SCN:0x0000000039031be5 (956505061) to follow new branch
 rfs (PID:1286351): New Archival REDO Branch(resetlogs_id): 1177883943  Prior: 1115909325
 rfs (PID:1286351): Archival Activation ID: 0x9cc516c2 Current: 0x9c3156ad
 rfs (PID:1286351): Effect of primary database OPEN RESETLOGS
 rfs (PID:1286351): Managed Standby Recovery process is active

there has been no such activity on the primary database which has resulted in such behavior. Can someone explain this?