This message occurs if Q++Studio notices that the text used as Xpress Tags contains what looks like a token (ie. an opening brace [ followed later by a ] closing brace). This message, which will contain additional information about its context, informs you that any tokens that are found inside the Xpress Tags text will be ignored (ie. these tokens will not be converted). This is one of the rare cases when token recursion does not function seamlessly, although special characters tokens do function as expected within Xpress Tags text.
It is important to note that this message comes from the use of tokens within the text specified for Xtags text (for example the text used for 23/30 and 24/31 combined dates in 5-week minicalendars). This message will not be generated if there are tokens inside the value of sResult and you are using Xtags as text replacement for a macro token (in that case the tokens contained in sResult will be converted as expected).
Finally, note that due to the codified nature of Xpress Tags, it is possible that a pair of opening and closing braces that is not a token. in that case you can ignore this message, which is only a warning and which does not interfere with further evaluation of the current token and its Xpress Tags text.