This article provides sFlow Limitations on Switches
Before this document was updated, there was only the following sFlow limitation. It was except that EX3400, EX4100, EX4300, EX4400, and QFX5K series switches use pseudo-egress sampling.
This causes customer concern between the actual behavior and the sFlow limitations.
The document is updated by some PR as follows.
https://uat.juniper.net/documentation/test/us/en/software/junos/network-mgmt/topics/topic-map/sflow-monitoring-technology.html#id-overview-of-sflow-technology__d122e1729