After upgrading JMX bridge to 1.8.x, you notice that some information presented through JMX is unexpectedly displayed as null. Also, the nodes for each job are ordered by GUID within the JMX mbean hierarchy, instead of by index, as was the case with older versions.
This is a known configuration change. The Firehose began to send the dropsonde envelope index as a GUID instead of an integer. The OpenTSDB nozzle, if enabled, continued to assume parsing by integer causing some null values to be output. As of v1.8.6, the OpenTSDB nozzle now correctly parses the index field as a GUID.
Starting with PCF 1.8, the way that metrics are reported through the Firehose has changed. This comes as a code change to Loggergator, and it results as a GUID being passed as the envelope index instead of a numeric index. As noted above, the JMX Bridge was previously parsing this value and expecting an integer. When this changed, the parsing broke, and null values were introduced. The resolution is to upgrade to JMX Bridge 1.8.6+, which has a code fix and correctly parses the values.
As mentioned previously, this also results in a change to the order beans in JMX, as the index went from numeric to string based. There is no way to revert to the previous numeric based indexing. Also, please note that Bosh metrics are still displayed by job index and not by GUID.
Please refer here for further details.