Brocade ICX 7450 one LAG interface up and down issue

[pradeep_sonawne]

Hi experts,

we have brocade ICX 7450 switches, using for Core and distribution, core and distribution are connected to each other by LAG.
one of the distribution's LAG interface port getting up and down continuously. i have checked there no any cable issue, no CRC errors on both interface , even i enabled optic monitoring on distribution's interface eth1/2/1 to check if there any optic issue, but that also ok.

i unable fix the issue, need your help to  fix the issue

Configuration as below 
-------------------------------------------------------------
Core Switch

lag 4WH dynamic id 4
 ports ethe 1/3/4 ethe 2/3/4 
 port-name "##Connected to 4WH DIST eth 1/2/2##" ethernet 1/3/4
 port-name ###Downlink_To_DIST### ethernet 2/3/4
-------------------------------------------------------------
Distribution switch

lag 4WH dynamic id 1
 ports ethe 1/2/1 to 1/2/2 
 port-name ###Uplink_to_Access_SW### ethernet 1/2/1
 port-name ##Connected_to_5.1_CoreSwitch_onPort_1/3/4### ethernet 1/2/2
--------------------------------------------------------------


Log on distribution

Fri Feb 22 04:23:55 2019;10.12.5.16; <14> Feb 22 04:23:56 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:24:00 2019;10.12.5.16; <14> Feb 22 04:24:01 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 
Fri Feb 22 04:24:00 2019;10.12.5.16; <14> Feb 22 04:24:01 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:24:08 2019;10.12.5.16; <14> Feb 22 04:24:09 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 
Fri Feb 22 04:24:09 2019;10.12.5.16; <14> Feb 22 04:24:10 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:24:27 2019;10.12.5.16; <14> Feb 22 04:24:28 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 
Fri Feb 22 04:24:28 2019;10.12.5.16; <14> Feb 22 04:24:29 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:27:46 2019;10.12.5.16; <14> Feb 22 04:27:46 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 
Fri Feb 22 04:27:46 2019;10.12.5.16; <14> Feb 22 04:27:47 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:27:47 2019;10.12.5.16; <14> Feb 22 04:27:48 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 
Fri Feb 22 04:27:48 2019;10.12.5.16; <14> Feb 22 04:27:49 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state down 
Fri Feb 22 04:27:48 2019;10.12.5.16; <14> Feb 22 04:27:49 WL_P1_D4-4WH-FA_L3-B7450_5.16 System: Interface ethernet 1/2/1, state up 



Note : this issue suddenly started otherwise everything was good.

OS ver on both switches : ver 08.0.70bT213

Thanks