Namespace prefix 'ns122' used but not declared.

I am editing the existing Integration mapper which is in code mode, In mapper we used variable and for-each-group and this integration was built in Gen 2 so we cannot edit in graphical mode, I need to add logic to loop the readfile, but when I cloned and removed all variable and for-each-group added my logic and copied code and used in previous integration getting below error and tried in same integration without saving but getting same error.

Error during evaluation of XPath "ora:doXSLTransformForDoc('resources/processor_89/resourcegroup_92/req_81a22ca0cf4a49a4a5e2aa78d2000f73.xsl', $messagecontext_9492)" Namespace prefix 'ns122' used but not declared.