We get the same issue with Openfire 3.5.0 RC1, Spark 2.5.7 or 2.5.8, running in MojoPac Free 1.8. The system time is correct, the server time is correct, but Spark’s timestamps are behind by 1 hour.
Other than that, Openfire and Spark work beautifully.
there’s none I’m aware of if you want to use the MSI installed Spark.exe.
If it’s possible for you to maintain and distribute your own files you may want to take a look at Spark.cmd start script. There you can set the parameters without issues.