I've seen "smoke on the horizon" before, when I decided to go topside and scan the horizon myself.
Strange that the captain can see it but the lookouts can't.
It happens infrequently, and such contacts that I investigated turned out to be merchantmen, but it does happen.
A couple of such contacts turned out to be 2 merchants steaming together in line formation.
But at least you spotted a TF - the only warships I've encountered that were not escorting convoys are DDs and smaller on (presumably) ASW duty. Not seen a CL or better in my 14 patrols thus far.