Once I noticed in the BDCOM P3608-2TE logs:
Alarm LASER_ALWAYS_ON from OLT 0x03000000 port EPON0/2 Alarm LASER_ALWAYS_ON from OLT 0x03000000 port EPON0/1
This alarm reports that the ONU continues to send optical signals for a long period of time, noticed this problem with SFP modules from the same manufacturer, and ONUs were generally from different manufacturers, well, users had no problems with the Internet, the signals were excellent, therefore I just turned off notifications so as not to clog the logs:
interface EPON0/1 epon onu-always-laser-on disable interface EPON0/2 epon onu-always-laser-on disable interface EPON0/3 epon onu-always-laser-on disable interface EPON0/4 epon onu-always-laser-on disable ...
An example of viewing the optical layer of all ONUs on a specified port:
show epon onu-ctc-optical-transceiver-diagnosis interface EPON 0/1
See also my article:
How to view information about ONU on BDCOM OLT