Initiator logged out from the switch

Hello,

We came across an issue where an initiator (ESXi host)  logged out from the switch and logged back in after a few min. Investigation from the OS logs reveal that initiator has been forced to log out upon receiving communication from a target (Storage array port). May I know under what circumstances would the SP port communicate to the initiator to log off? We could say SP is busy, but this happened only to one initiator and not on all initiators. Also, during the issue, I didn't see heavy utlization on the initiator.