This article explains the significance of the below logs,

Feb 19 01:45:09 router-r1 rpd[28729]: %DAEMON-4-JTASK_NONBLOCKING_SOCKET_IO: sending 1024 (sent 0) bytes to local failed: Socket is not connected

Feb 19 01:45:09 router-r1 rpd[28729]: %DAEMON-3-JTASK_NONBLOCKING_FILEOP: read for task local socket -1: Socket is not connected

Feb 19 01:45:09 router-r1 rpd[28729]: %DAEMON-4-JTASK_NONBLOCKING_SOCKET_IO: sending 1024 (sent 0) bytes to local failed: Socket is not connected

Feb 19 01:45:09 router-r1 rpd[28729]: %DAEMON-3-JTASK_NONBLOCKING_FILEOP: read for task local socket -1: Socket is not connected

This messages are reported due to Error while reading or writing from non-blocking socket.

Based on syslog explorer this is seen while reading or writing from non-blocking socket. The read-operation for this socket stream failed with error, resulted in rpd reports non-blocking file operation error while reading. 

https://apps.juniper.net/syslog-explorer/?msg=JTASK_NONBLOCKING_SOCKET_IO&sw=Junos%20OS&rel=21.4R3

This is an information log message, non-impacting.

It is due to Error while reading or writing from non-blocking socket and the socket was not connected at that particular time when the log was reported.

This will not be continuous.