RS: Added known issue for the metrics stream engine latency metrics to RS 7.22 release notes

Author: rrelledge

content/operate/rs/release-notes/rs-7-22-releases/_index.md

@@ -115,6 +115,8 @@ The following table provides a snapshot of supported platforms as of this Redis
 
 - RS156391: The `job_scheduler`'s memory usage can increase significantly when the diagnostic logging service is enabled.
 
+- RS153589: The metrics stream engine preview reports incorrect latency metrics.
+
 ## Known limitations
 
 #### Upload modules before OS upgrade

content/operate/rs/release-notes/rs-7-22-releases/rs-7-22-0-95.md

@@ -290,6 +290,8 @@ The following table shows the SHA256 checksums for the available packages:
 
 - RS156391: The `job_scheduler`'s memory usage can increase significantly when the diagnostic logging service is enabled.
 
+- RS153589: The metrics stream engine preview reports incorrect latency metrics.
+
 ## Known limitations
 
 #### Upload modules before OS upgrade