I recently stumbled into an interesting issue with the latest recommended release for the Juniper EX4400 switch running software release 22.2R3-S2.8. The LLDP table was missing the entries for the neighboring Juniper EX4650 switch that it was uplinked to.
Long story short it turns out that this is a known issue.
You need to add the following configuration statement to your adjacent switch, not the EX4400 itself but the switch on the “other” side of the connection
set protocols lldp tlv-filter cloud-connect-event
With that statement in the EX4650, the EX4400 would display the appropriate neighboring links in it’s LLDP table.