Doesn't really surprise me when you have other issues like this (https://github.com/npm/npm/issues/17929) that have persisted for a long time. NPM 5.x in general hasn't been very stable.
Indeed. Another odd thing that it's been doing lately is when I run some NPM scripts on one of our machines, it starts shouting about some sort of update not working (why was it updating anything at all just because I ran `npm run something`?) and gives me instructions on how to fix it from the Linux shell (on a Windows box). The depth of failure implied by that message is disturbing on several levels.