SFP module transmit fault

with 4.x alpha5 the log showing

libphy: SFP I2C Bus: probed
sfp sfp: module ALLNET ALL4781 rev V3.4 sn 0000000FC9157640 dc 29-03-18
sfp sfp: unknown connector, encoding 8b10b, nominal bitrate 1.3Gbps +0% -0%
sfp sfp: 1000BaseSX+ 1000BaseLX- 1000BaseCX- 1000BaseT- 100BaseTLX- 1000BaseFX- BaseBX10- BasePX-
sfp sfp: 10GBaseSR- 10GBaseLR- 10GBaseLRM- 10GBaseER-
sfp sfp: Wavelength 0nm, fiber lengths:
sfp sfp: 9µm SM : unsupported
sfp sfp: 62.5µm MM OM1: unsupported/unspecified
sfp sfp: 50µm MM OM2: unsupported/unspecified
sfp sfp: 50µm MM OM3: unsupported/unspecified
sfp sfp: 50µm MM OM4: 2.540km
sfp sfp: Options: retimer
sfp sfp: Diagnostics:
sfp sfp: module transmit fault indicated
sfp sfp: module transmit fault recovered
sfp sfp: module transmit fault indicated
sfp sfp: module persistently indicates fault, disabling

Mind you the ALLNET ALL4781 is a small form factor DSL modem in the SFP port and works without these hiccups in TOS3.x branch.

Identifier : 0x03 (SFP)
Extended identifier : 0x04 (GBIC/SFP defined by 2-wire interface ID)
Connector : 0x22 (RJ45)
Transceiver codes : 0x00 0x00 0x00 0x01 0x00 0x00 0x00 0x00 0x00
Transceiver type : Ethernet: 1000BASE-SX
Encoding : 0x01 (8B/10B)
BR, Nominal : 1300MBd
Rate identifier : 0x00 (unspecified)
Length (SMF,km) : 0km
Length (SMF) : 0m
Length (50um) : 0m
Length (62.5um) : 0m
Length (Copper) : 255m
Length (OM3) : 0m
Laser wavelength : 0nm
Vendor name : ALLNET
Vendor OUI : 00:0f:c9
Vendor PN : ALL4781
Vendor rev : V3.4
Option values : 0x08 0x00
Option : Retimer or CDR implemented
BR margin, max : 0%
BR margin, min : 0%
Vendor SN : 0000000FC9157640
Date code : 18032900