There is no true DRI for vitamin D or upper toxicity limit yet as it is so highly dependent on each individual.
Clinical research does suggest a regular dose of 3000-5000 is necessary to maintain adequate levels whilst this is vastly different to government recommendations which are notoriously ill-informed.
Blood testing is required to understand the state of each person and their required dosing. 100nmol/L is generally considered adequate whilst some have found 200nmol/L is beneficial whilst borders toxicity. To get to this level supplementation can be administered up to 40,000iu over 6 weeks or 20,000iu over 12 weeks then a maintenance dosage.
This is often given as an intramuscular bolus injection which would obviously be a very large dose rather than daily oral supplementation (maybe this is what happened?) but interestingly this has seen to not be effective as smaller daily doses.
Skin pigmentation does blunt the effect of Vitamin D synthesis from sunlight so it wouldn't be unheard of for an athlete to still require supplementation.
The half-life of vitamin d can be as short as 4 weeks from a dose that maintains adequate levels.
Perhaps this helps clear up Vitamin D, not whether any rules were broken but just it as a supplement.
Cheers