Nullpointer after submit in selectonemenu

im using primefaces selectonemenu to set the value of a variable in a @RequestScope bean with wich i seek to grab specific data from a entity. The goal is with that set String i want to populate a chart on the same site as the selectonemenu is on, depending on the choosen value. So the chart reloads with the data depending on the choosen value 'selectedTime'.

<div>
     <h:form id="form-select-transaction">
            <p>Transaktion wählen:</p>
            <h:selectOneMenu value="#{transactionBoundary.selectedTime}"
                             id="quickselect-transaction"
                             onchange="submit()"> 
                <f:selectItem itemLabel="Select One" itemValue=""/>
                <f:selectItems value="#{transactionBoundary.list}"/>
            </h:selectOneMenu>
            <!--<h:commandButton value="Submit" action="result"/>-->
        </h:form>
    </div>

The transactionBoundary.list is, for now, just a List of Strings generated in the bean.

The 'selectedTime' i use to grab from a @Stateless store data from DB.

Now the Site loades just fine but when i select one Value from the selectonemenu i get a nullpointer. I have multiple sites like this (also requestscoped) and all are working fine, i have no idea why this is not working, hopefully someone can help me, ive spend already two days trying to fix it without any success :/

Greetings