I guess it's true, it maybe a random selection and sheer luck... but my theory though is that USCIS has outsourced various different agents to help in the processing of cases to approval and send to NVC...For example ; they choose a lumpsum of cases submitted in like three consecutive months and distribute them to different agents and now your fate lies in a certain unknown agent with his/her own work ethic...This causes a delay for some cases and swiftness in some😢😢 my thinking though....
Unfortunately, NVC only sent an email informing us that our case has been sent to the Embassy and that the proces can take several weeks😂😂. With our case numbers but no invoice ID....so there was no way we could track it on CEAC...SO after seeing from this forum people tracking their progress, I wrote to NVC requesting for INVOICE ID, they politely replied that they don't have my case anymore and I should contact the Embassy for inquiries so all I can do is WAIT🤨