Investigate step portal runtime error

Hellow experts ,

We are on ne portal 7.3 ehp1 sp07 and ehsm bp for portal is on ehsm 3.4 version,

we are getting portal runtime error when from work overview powl we execute an incident investigation workflow ,when we click on under investigation tab --investigation flow ---some entry ,we get portal runtime error,in portal logs following error appears :which is caused by :

"Caused By java.util.missingResourceException: Cant find resource for bundle java.util.propertyResourceBundle,Key Error Node Tiltle"

Scenshot attched:

Any help ,suggestions are most welcome.

Thanks,

Siddharth