Smartfilter mask isn't transforming

You should be able the Transform a Smart Filter Mask itself.  What you can not do is Link the Smart Filter Mask to the Smart object.  While it look like you can link a layer mask on the Smart Object layer to the Layers Content content. Photoshop will allow you to set the mask to have the link icon when there is warping.  There are restrictions when it come to smart object later, If you transform the Layer's content Photoshop may pop up a messages stating  no no Smart Object can not have linked layer mask.   The Smart object can be edited the object itself can have layers will linked mask as long as its not an other smart object layer.   Photoshop does not support linking mask to smart object.    So if you transform a smart object you may need to re do the masking. You may be able to do it by un-link the mask and transforming the mask itself.  However the transforming your are doing to the smart object  warping may be difficult to replicate the warping of the mask.  Also a  smart object layer can only have a single filter mask all smart filter on the layer will be masked by the same filter mask. Will the current smart filters setting be appropriate for the transformed object. You may need to also readjust all the layers smart filters settings.