That would indeed be a bug.
Unfortunately, I can't reproduce it. Here's the code I ran which worked:
Page 1:
<h:body>
<h:form>
<h:commandLink immediate="true" action="two">ONE
<f:param name="dataId" value="one"/>
</h:commandLink>
<br/>
<h:commandLink immediate="true" action="two">TWO
<f:param name="dataId" value="two"/>
</h:commandLink>
<br/>
</h:form>
</h:body>
Page 2:
<h:body>
#{param.dataId}
</h:body>
Please modify it so it fails, then I can help.
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