webpack is not mangling @effect/data/mjs/* properly

/**
 * @since 1.0.0
 */
var _a, _b;
/* [...] */
export class Some {
  [(_a = EffectTypeId, Equal.symbol)](that) { // <----------------------------here
    return isOption(that) && isSome(that) && Equal.equals(that.i0, this.i0);
  }
 /* [...] */
  constructor(i0) {
    this.i0 = i0;
    this._tag = "Some";
    this._id = TypeId;
    this.i1 = undefined;
    this.i2 = undefined;
    this[_a] = effectVariance; // <------------------------------------------here
  }
  pipe() {
    return pipeArguments(this, arguments);
  }
}

  constructor(i0) {
    this.i0 = i0;
    this._tag = "Some";
    this._id = TypeId;
    this.i1 = undefined;
    this.i2 = undefined;
    this[EffectTypeId] = effectVariance;
  }