So.. to be clear.

You got the Riddle of Battle done. You got the Riddle of the Hunt done.
You got the Riddle of War done.

You chose 3 of the 6 to complete, the quest is done isn't it?

I have a similar problem.

I cannot solve the Riddle of War.

I have been in all three Cyrodiil Delves, defeated bosses and mobs, but I can never interact with the books, the "Heartlands Mindpuzzles" I am supposed to pick up to solve the riddle.

They are laying on the ground, surrounded by a swirl, but there is nothing I can do.

EDIT: I saw in my quest item inventory that I already picked up one of the Heartlands Mindpuzzles. However, they are stil higlighted on the ground in the delves, and the quest does not progress.

EDIT 2: I found out that you can just do any of the other "riddles" that are offered in the solutions book under quest items. So, even though, the riddle of war never seemed to have progressed, the overall quest has done so by doing other stuff, like picking up the flowers in the monastery in Reapers March.

TLDR:
Even though "riddle of war" does not indicate that it has been solved, you can continue with other riddles in order to progress. It would help if the descriptions were clearer, and if there was an indication given when you progressed instead of pointing to the delves only. Especially for the Cyrodiil part, because I really went to all three delves which was a risky waste of time.

^^^ My experience, too-- NPC matches count. I didn't try against another player.

The only riddle that acted buggy for me was the one for three delves in Cyrodiil. I went to the first delve, killed the bosses and a lot of mobs, but it didn't count. I went to the second delve and there was a quest item in a glowing circle that had a quest pointer to help you find it, and looting that worked. I assume the first delve had something like that in it, too, but I didn't see it.

The wording makes it sound like you need to complete the three delves in the riddle, or kill all six world bosses, etc., but you only need to do one to get credit.

DragonRacer wrote: »

I recognized the Riddle of the Game being ToT right away, queued a ranked match won, did not count.

Guess I will try to find an NPC in Reaper’s March to play…

The Proficient one in Rawl’kha counted for me.

NeoniKa wrote: »

Oh! So, it's bugged... Ok.

I've been trying the Riddle of the Game, I read that the idea is to win a Tales of Tribute match, but it doesn't say anywhere how many times. Meanwhile I already won more than 6 matches both in casual and ranked and nothing happens.

So, I guess it's better to just cancel the Drangon quests for now and move on to Gryphon.

Play against an NPC and it should count.