Nope, Oakmont could only be played all at once, before somebody screwed up and let custom courses include Oakmont holes.
Only two possible reasons for the parting of the ways, at least the way I see it.
1) Oakmont got thoroughly pissed about the above. If this is the case, new employment opportunities should show up in San Francisco rather soon.
2) The contract was up, Oakmont wanted more dollars to re-sign and the Top Golf bean counters declined the offer. If this is the case, it was a pure business decision for each party.
It would be nice if WGT would be a bit forthcoming and clear the air, but I don't see that happening.