'Group multiple values' makes fields disappear

Issue Summary

I have profiles made with Bio module, in which I have some cck fields with multiple values allowed.

Then I installed Usernode to use its better Views integration (displaying/filtering/sorting by last access/last login).

So I edited my View, changing the 'Node:type' filter from 'My_profile_type' to 'Usernode'. This made the field with multiple values disappear. If I change handler from 'Group multiple values' to 'Do not group multiple values', the values are back (obviously one per row, which is not what I want). Values are not shown also if handler is 'Show first only' or 'Show last only'.