Hi Mel,
welcome to the KNIME Forum 
Would you by any chance be able to share a small reproduction workflow, so that others can easily look into the issue on their machine?
A shared workflow also helps identify the KNIME version in use, in case you’re experiencing a bug that may be fixed in a later version.
In general, you’ll find a few tips on crafting questions to get quick answers on the forum here.
Kind regards
Marvin