Override Exclude Problem

2 different jobs, both using Xref’s and around 200 Vray proxies.

I select the vray proxies to be excluded and they appear in the list, all good.

When I render I see some of the trees (vray proxies) have not been excluded but whole xrefs or parts of them have been.

I then check back in the exclude list, which shows some of the original vray proxies I selected plus a whole heap of different objects.

I remove the unwanted objects and re-pick the vray proxies to be excluded, but the list shows again the other unwanted objects.

Whats going on, is this a bug?

XP64 SP2 --- Max 2009 SP1 --- Vray SP3a