When someone writes a book about this war, and in particular this 60 km long static convoy, there will be an interesting chapter on the real reasons that it did not move. (I get the explanation that vast convoys can only realistically move 50 km a day for logistical reasons.)
Speculation warning.
If there is any truth in this 'mutiny' over the Odessa landings, then could there be loss of morale and discipline within the ranks in the army convoy? Are there rogue generals even, or troops that have spent time on the available internet, refusing to move if they are not 100% welcome in Ukraine?
Or are they waiting for the cities to be mashed to pulp first by incoming fire? If the latter, then Putin needs to know NOW that they are sitting ducks and that he will lose his youngest and finest if he ever unleashes his war crime on the cities.
Or has Putin set up a dummy convoy waiting for it to be attacked, offering him a pretext to attack the cities? They seem to be parked temptingly close together.