Taken from the comments section of the DT:
"The decision of race officials to ignore their own safety car rules was disgraceful. rule 48.2 of the FIA rules clearly states 'If the clerk of the course considers it safe to do so, and the message "LAPPED CARS MAY NOW OVERTAKE" has been sent to all Competitors via the official messaging system, any cars that have been lapped by the leader will be required to pass the cars on the lead lap and the safety car.' Not just the cars between Hamilton and Verstappen. The rule also states. 'Unless the clerk of the course considers the presence of the safety car is still necessary, once the last lapped car has passed the leader the safety car will return to the pits at the end of the following lap.' In this instance the safety car didn't wait until the following lap to leave but left on the same lap."
If true, then Mercedes may have a strong case to challenge the result.