Was this Delta Rep correct about missing Miles?

So I called Delta about the last leg of a trip not giving milage with the reason code N although the first two legs of the trip have given the mileage. The last flight was delayed in AMS because of weather and rebooked to a later flight and after that, the Fare code changed to R instead of X for that flight on KLM AMS-GOT. I waited a few days then emailed Delta and they said they fixed it, but then it just showed up in the activity but not showing any Mileage saying that it isn't eligible for any miles. That is when I called Delta and the Rep said that in order to get the miles I need to get on the return leg in November to confirm that I actually took the flight last week. That doesn't make sense to me as I've flown both KLM and KLM city hopper and always gotten the mileage a day after the Delta operated legs cleared and not have had to return to the US for it too clear.

So was she correct? I just haven't ever experienced this or heard of it before.

I've never heard of this, but do you have your boarding pass for the segment in question? If you have some evidence that you took the flight, it might be easier to just send it to DL.

Yes, I have it, I just would think they can see in the system if someone took a flight or not.

HUCA but perhaps the rebooking somehow wasn't communicated correctly to DL.

A BP, of course, is proof of nothing other than the fact that OP at some point was ticketed and held a reservation. One would have a BP even if one deliberately no showed. That is why the IRS stopped requiring US businesses to collect BP's over 20 years ago.

What most likely happened is that when OP boarded his KL flight, the BP did not scan nobody at KL went back and figured out who boarded and did not scan. Thus, DL is looking for a way to figure this out.

You could call back and hope that the agent did not note the PNR, or you could just wait until you fly the return (which also proves nothing more than that your ticket wasn't cancelled).

OP says the fare code for the missing flight was booked as X, but later changed to R. Maybe Delta's system thinks the segment is an award flight?

I had a similar situation during the "Great Disruption" earlier this year. After several attempts at correcting the issue, I finally talked to a rep who realized; "There's no revenue attached to that leg". She then touched some magic keys and the problem was solved.

...which of course it can't be - you can't have a single PNR/ticket that is revenue in one direction and skymiles in the other direction - such a ticket is simply impossible. DL needs to fix this - just keep reaching out to DL until you find that proverbial agent who understands the big picture.

Yes, I will have to keep calling them. I just wish all the agents were equally as knowledgeable about Delta. It is strange though that the fare changed to R from X.

Ok, 2nd try was a success. The agent immediately knew what the problem was and had the SkyMiles department fix it. Apparently, since KLM reticketed the flight it had a different ticket number.