Situation:- When you use double quotes in context.put() function in data mapper that is further used in Process Flow (PF) designer. PF shows an error "not a valid variable name for context variable". Even if you try to rename variable it would still point to the old variable and shows the same error.
Solution:- In the custom plugin code, mention the String using double quote, for example: Context.put("Key","value").
In XML, mention the String in single quotes. For example, set-context('TotalRec' ,'one' ).
Avoid writing the context variable in double quotes in the mapping context variable.