Cannot read property 'map' of undefined #3840

 6.8.0

            }
            transaction.setTag('lcp.size', this._lcpEntry.size);
        }
        if (this._clsEntry) {
            logger.log('[Measurements] Adding CLS Data');
            this._clsEntry.sources.map(function (source, index) {
                return transaction.setTag("cls.source." + (index + 1), htmlTreeAsString(source.node));
            });
        }
    };
    /** Starts tracking the Cumulative Layout Shift on the current page. */

                    op: 'web.vitals',
                    startTimestamp: this._measurements['mark.fid'].value,
                });
            }
            transaction.setMeasurements(this._measurements);
            this._tagMetricInfo(transaction);
        }
    };
    /** Add LCP / CLS data to transaction to allow debugging */
    MetricsInstrumentation.prototype._tagMetricInfo = function (transaction) {
        if (this._lcpEntry) {