yalc.lock entry:

    "@what/ever": {
      "signature": "012344568987987",
      "file": true,
      "pure": false
    },

Will be replaced with "pure": true when @what/ever is yalc push because of the line:
https://github.com/whitecolor/yalc/blob/30d0cc7c933c41b71e578244b07538acae1085d6/src/update.ts#L54

Does not respect yalc.lock configuration at all, but unpreventably forces the --pure default via subsequent:

https://github.com/whitecolor/yalc/blob/30d0cc7c933c41b71e578244b07538acae1085d6/src/add.ts#L116

Says to use --no-pure, but --no-pure can't be given to yalc push, and earlier yalc add --no-pure is not respected.