java.lang.NullPointerException on Kettle 4.4.0 LoggingRegistry

Hello,

We have been using Kettle 4.1.0 for more than a year to load some files into an ORACLE Database and recently we upgraded to Kettle 4.4.0.
After the upgrade, sometimes we have the following error and we need to start over again to finish the process:

Unexpected error occurred while launching entry [job_trans_principal_cvm.0]
at java.lang.Thread.run (null:-1)
at org.pentaho.di.job.Job$1.run (Job.java:703)
at org.pentaho.di.job.Job.access$000 (Job.java:103)
at org.pentaho.di.job.Job.execute (Job.java:617)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer (Log4jBufferAppender.java:167)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer (Log4jBufferAppender.java:171)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer (Log4jBufferAppender.java:158)
at org.pentaho.di.core.logging.Log4jBufferAppender.getLogBufferFromTo (Log4jBufferAppender.java:150)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:207)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren (LoggingRegistry.java:221)
at java.util.concurrent.ConcurrentHashMap.get (null:-1)

at org.pentaho.di.job.Job$1.run(Job.java:709)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at java.util.concurrent.ConcurrentHashMap.get(Unknown Source)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:221)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:236)
at org.pentaho.di.core.logging.LoggingRegistry.getLogChannelChildren(LoggingRegistry.java:207)
at org.pentaho.di.core.logging.Log4jBufferAppender.getLogBufferFromTo(Log4jBufferAppender.java:150)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer(Log4jBufferAppender.java:158)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer(Log4jBufferAppender.java:171)
at org.pentaho.di.core.logging.Log4jBufferAppender.getBuffer(Log4jBufferAppender.java:167)
at org.pentaho.di.job.Job.execute(Job.java:617)
at org.pentaho.di.job.Job.access$000(Job.java:103)
at org.pentaho.di.job.Job$1.run(Job.java:703)
... 1 more

Can somebody help us with this issue?