Almost all positions of panpsychism claim that an aggregate of objects does not constitute a distinct experience by itself. This position is not a contradiction, as long as the objects themselves can have experience. For example, one does not think of a group of people as a distinct conscious entity apart from the actual people themselves.
Excluding bosons from having this attribute, does not invalidate the claim of panpsychism, nor invalidate any consciousness conservation law, if there is such (whatever the case).
For example a Cooper pair of electrons behaves as a boson, while at the same time it is an aggregate. On the other hand, a photon can also be expressed as a kind of interaction between an electron and a positron.
So aggregates behave as bosons and bosons may be aggregates, thus it is dubious whether it consists of a separate experience apart from what the electrons themselves may have.
Note that there are conditions, under which an aggregate, can be a distinct conscious entity, eg all biological organisms, humans among them, are types of aggregates. So this claim is not absolute.