Nothing in the MUTCD could possibly kill the citation. The MUTCD isn't binding. Anyhow, the closest thing you'll find is
Placement of a traffic control device should be within the road user’s view so that adequate visibility is
provided. To aid in conveying the proper meaning, the traffic control device should be appropriately positioned
with respect to the location, object, or situation to which it applies. The location and legibility of the traffic
control device should be such that a road user has adequate time to make the proper response in both day and
night conditions.
Note that the "should" here in standards speak isn't binding, so even if MUTCD was binding, it wouldn't be an absolute requirement.
Further, while it's hard to tell with the limited picture provided, it would appear that if you actually STOPPED at the limit line the turn restriction would be perfectly legible and since you were stopped anyhow, it would be no problem with having "adequate time" to make the proper response.
Donzoh will be by with non-specific roll-the-dice technicalities.