As soon as you import, any updated rule gets updated in pr_sys_updatescache table with particular node-id in pzNodeName. So there should be an entry for this updated rule in this table with node1 reference. System pulse on node2 will take care of querying this table and updates it's local cache.
Need few details to get more clarity in here -
1. Have you observed this behaviour on any rule types post-deployment on Node2? or specific to one rule?
2. What is the PRPC version ?
3. How did you deploy RAP file on Node1, using Import wizard or Command line ?
4. Have you tried restarting the system pulse agent directly on SMA if it's a lower environment to validate this behaviour ?