ros 6.6 dhcp-client cannot renew on sfp1 on 2011UAS-2HnD

hello

we have a problem with dhcp-client, after expiring it cannot renew lease.
in the GW ,there is in log following :
offering lease IP for MAC without success

  • the dhcp client is on interface sfp1
  • after reboot the dhcp client gets the IP address
  • manual renew causes the same problem,cannot get ip address
  • downgrading to 5.26 solves the problem
  • this problem occurs on all 6 pieces of RB2011 connected on the same switch

could you please suggest a solution?
thank you very much.

gateway : RB1100 ros 6.6
switch : TP-LINK TL-SG5412F
client: 2011UAS-2HnD ros 6.6
gbic module: SPB-7603CIS OEM Mini-GBIC module (SFP), 1000Base-BX10, WDM singlemode 3km, LC, Tx 1310,Rx 1550, cisco comp.