I crimp multi-strand when the terminal is a screw that rotates as it is tightened down onto the conductor. Too often a few strands get cut by the rotating screw, or they move sideways from under the screw and the screw then does not put any pressure on them. Some 13 amp plugs especially.
Partex CEFT 1 is very good economically priced crimper for bootlace ferrules
https://www.rapidonline.com/partex-ceft1-bootlace-ferrule-crimping-tool-85-0275
i see this as well especially when you take the wring out for any reason...new plug etc
i double the end over...do you think that helps?