Hey there, in those cases, you need to add a socket with alias e_bone and attach it to one of the mob's bones, which you're missing:
You can use these buttons to check what bones the mesh has
should end up looking something like this:
Remember to add a small Z offset, or the abnormal effects will be inside of the mob's head. Usually an offset of 20-25 works fine.
Also, when you type Bip01 HeadNub in the BoneName field, you might see that when you press enter it gets saved as Bip01, without HeadNub. To avoid that, type the bone's name in double quotes: "Bip01 HeadNub", then press enter
Also, there's a nice little trick that you can use to not lose any mesh properties (LOD, rotation, location, etc) so you don't need to export > re-import the .psk file whenever you wanna edit something, if you wanna know, send me a DM on Discord