Hi,
When you opened case with TAC & they confirmed that 3rd party optic aren't supported, these related logs are generic arcoss platforms and expected to see when using unqualified transciever. Here i have another juniper node with an non qualified SFP:
Apr 4 00:04:17 2018 sfp-0/0/17 link 17 SFP receive power low alarm set
Apr 4 00:04:17 2018 sfp-0/0/17 link 17 SFP receive power low warning set
Apr 4 00:04:33 2018 sfp-0/0/16 link 16 SFP receive power low alarm set
Apr 4 00:04:33 2018 sfp-0/0/16 link 16 SFP receive power low warning set
Apr 4 00:04:49 2018 sfp-0/0/17 link 17 SFP receive power low alarm cleared
Here is list of qualified transceivers (product wise)
https://apps.juniper.net/hct/category/#catKey=100001&modelType=All&pf=EX+Series