I don’t have a tag for “bad grounds for a GAO bid protest,” but if I did, challenging an agency’s decision not to conduct discussions would fall in that category–at least (as is typically the case), when the solicitation does not state that discussions will be conducted.
This issue comes up often enough in GAO bid protest decisions (with the same predictable result nearly every time) that it’s worth taking a quick look at one such recent case in which this particular issue arose.