. In corrosive environments, stranded wire will corrode into the crimmped terminal and around the wire, insulating the wire from the terminal slightly causing it to burn, then fail.. thats common.
Accordingly battery cable manufacturers most often solder their wire into the crimped terminal ends.
This practice is seen pervasively in marine environments on both low amperage control circuits, and on power circuits.
Use of solder on power circuit terminals however has many problems, namely the solder melting out of the joint if the wire warms too much...and extrusion of the solder under compressive stress if screw connectors are used.. the military specs some are referring to cover that aspect... but not the other aspects.
Use of solder in an already crimped terminal serves to increase the electrical contact area, thats good, and to preclude corrosive gases, vapors and oils from the joint (by wicking up the bare wire).... that is seen commonly be the cause of failure in those situations.
For the last 100 years... and currently.... most if not all controls systems and component manufacturers dip wire ends in solder that are to be fit under screw head connectors... the practice is at least 90% common.... thats with *control circuits.
The practice is not common with power circuits for the reasons mentioned but is still seen in some situations (primarily corrosive environments... anyone can purchase NEC approved soldered connectors of course for those purposes... those are also pervasively common, especially in the electronics industry.)
Phil Scott Mechanical/ Electrical engineer and industrial controls contractor since 1852 (I'm very old)