Error while using message tokens

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Hi All,

We have a requirement to validate maximum duration limit by storing the max limit in a UDT. We have defined an Error Message and have defined a message token which picks the value from UDT and calling the message in the formula. But while adding an absence, I'm getting the error "Contact your absence administrator with the following details: Module AbsenceEval, Method validateUsingFormulaFromUi and Error Exception occurred during validation formula execution. java.math.BigDecimal cannot be cast to java.lang.String."

Please note that the error is not appearing when I don't use message tokens. Below is the formula code I'm using. What mistake I'm doing here?