Remove duplicated options in boot options, BIOS

Question

I have dual booted my laptop. I have multiple choice in boot options in BIOS that are duplicates. The Ubuntu option is sometimes gone when I shut down from Ubuntu. Why does Boot option keep on changing?

Output of efibootmgr:

BootCurrent: 0006
Timeout: 1 seconds
BootOrder: 0006,0001,0002,000D,000F,0010,0009,0007,0003,0011,0005,0004,000B,0013,0000,0012
Boot0000* Windows Boot Manager  HD(1,GPT,356a3f34-0c68-4dda-9435-9794d3317e65,0x800,0x32000)/File(\EFI\MICROSOFT\BOOT\BOOTMGFW.EFI)WINDOWS.........x...B.C.D.O.B.J.E.C.T.=.{.9.d.e.a.8.6.2.c.-.5.c.d.d.-.4.e.7.0.-.a.c.c.1.-.f.3.2.b.3.4.4.d.4.7.9.5.}...*!...............
Boot0001* UEFI OS   HD(3,GPT,61f5b5a1-36e8-4897-9f55-7ee30e6dd475,0x29706800,0x64000)/File(\EFI\BOOT\BOOTX64.EFI)..BO
Boot0002* CD/DVD Drive  BBS(CDROM,,0x0)..GO..NO........o.T.S.S.T.c.o.r.p. .C.D.D.V.D.W. .S.U.-.2.2.8.G.B....................A...........................>..Gd-.;.A..MQ..L.1.S.G.8.Y.6.G.H.0.B.D.5.0.Q. . . . . . ........BO
Boot0003* CD/DVD Drive  VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0004* CD/DVD Drive  VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0005* Hard Drive    VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0006* ubuntu    HD(1,GPT,356a3f34-0c68-4dda-9435-9794d3317e65,0x800,0x32000)/File(\EFI\UBUNTU\SHIMX64.EFI)
Boot0007* Hard Drive    VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0009* UEFI OS   HD(3,GPT,61f5b5a1-36e8-4897-9f55-7ee30e6dd475,0x29706800,0x64000)/File(\EFI\BOOT\BOOTX64.EFI)..BO
Boot000B* Hard Drive    BBS(HD,,0x0)..GO..NO........o.L.I.T.E.O.N. .C.V.1.-.8.B.2.5.6....................A...........................>..Gd-.;.A..MQ..L.V.C.-.1.B.8.5.2._.6.0.0.5.2.9.4.0.1.R.1........BO..NO........o.T.O.S.H.I.B.A. .M.Q.0.1.A.B.D.1.0.0....................A...........................>..Gd-.;.A..MQ..L. . . . . . . . . . .1. .E.6.T.X.H.Q.T.6........BO
Boot000D* UEFI OS   HD(3,GPT,61f5b5a1-36e8-4897-9f55-7ee30e6dd475,0x29706800,0x64000)/File(\EFI\BOOT\BOOTX64.EFI)..BO
Boot000F* Hard Drive    VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0010* CD/DVD Drive  VenHw(99e275e7-75a0-4b37-a2e6-c5385e6c00cb)..GO
Boot0011* UEFI OS   HD(3,GPT,61f5b5a1-36e8-4897-9f55-7ee30e6dd475,0x29706800,0x64000)/File(\EFI\BOOT\BOOTX64.EFI)..BO
Boot0012* ubuntu    HD(1,GPT,356a3f34-0c68-4dda-9435-9794d3317e65,0x800,0x32000)/File(\EFI\UBUNTU\GRUBX64.EFI)..BO
Boot0013* Network Card  BBS(Network,,0x0)..GO..NO........k.R.e.a.l.t.e.k. .P.X.E. .B.0.3. .D.0.0.........................rN.D+..,.\...........<..Gd-.;.A..MQ..L.R.e.a.l.t.e.k. .P.X.E. .B.0.3. .D.0.0........BO