Having the exact same issue, id you ever figure it out?
I have flagged for feedback from swtor , response will be on monday i would think
ok seems this occurs if the inventory is too full to contain both items from PH4-LNX Protocol Lockbox, the collections unlock also doesn't trigger.
if not done so yet you either need to create an ingame ticket if a subscriber , otherwise send an email from the email address you attached on the swtor account to support@swtor.com they can help resolve this for you
Ticket submitted.
Thanks
