SNMP V3 not working with "zabbix"

SNMPv3 authentication appears to work correctly when I try it in my lab (note that I set the OID field to .1.3.6.1, so that I could poll for system.sysUpTime, whereas you had it set to 1.3.6.1.4.1.3375, which is the F5 prefix, and would cause your box to return the error 'No Such Object available on this agent at this OID' if an object outside of that branch was requested)

snmpget -v3 -n "" -u snmpv3user -a MD5 -A "password" -x DES -X "password" -l authPriv 192.168.218.210 system.sysUpTime.0
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (323286) 0:53:52.86

05:21:54.920492 IP 192.168.218.11.35538 > 192.168.218.210.snmp:  F=r U= E=  C= GetRequest(14)
05:21:54.921615 IP 192.168.218.210.snmp > 192.168.218.11.35538:  F= U= E= 0x800x000x1F0x880x800x1D0x9F0x460x290xC50x770x660x57 C= Report(31)  .1.3.6.1.6.3.15.1.1.4.0=4
05:21:54.922027 IP 192.168.218.11.35538 > 192.168.218.210.snmp:  F=apr U=snmpv3user [!scoped PDU]a2_72_8a_b3_87_9f_e9_75_91_e8_31_ae_9f_8a_2e_60_d7_a3_cb_82_d8_1b_8d_24_b6_2e_2c_fe_24_67_95_74_c5_a1_29_27_e6_d6_4b_ff_04_3c_ea_77_d4_e1_55_53_cb_90_6c_83_d4_bc_b4_c1
05:21:54.922336 IP 192.168.218.210.snmp > 192.168.218.11.35538:  F=ap U=snmpv3user [!scoped PDU]d5_d5_bd_16_b2_d2_f3_76_07_b6_95_07_45_b6_ec_e5_ce_f1_64_d9_56_86_e8_2e_8d_68_8f_64_cc_78_60_46_8a_8d_d2_d6_4d_fa_01_91_2c_4e_eb_80_33_b4_c4_69_50_8e_43_8f_60_eb_cd_79

Does that command work for you if you change the username, auth password, and privacy password to the values you're using ?