uk3cb_baf_units_mtb.pbo are not signed (also TS question)
Regarding that error message: The 3CB Mod team released an update to one of our mods and the 3CB Public Server Manager had (has? Will check if fixed) not updated the server to that new version yet
Re-downloading the newest version wouldn't have fixed it since the server is set to only ever allow one version (so everybody has the same mods and we don't get weird glitches happening

)
For voice levels: In the windows volume-thingy I tend to bring Arma3 down to about 25% of the master-volume, but keep TS at 100% of the master-volume. That makes it a
lot easier to understand people.