The MACR is saying that this B-24 was flying a diversion mission. There was no raid on Germany by 8th Air Force that day, only B-26 attacks on French airfields, so I wonder if a diversion mission was launched and the main mission was cancelled.
It was usual for B-24 groups to fly diversion when B-17 attacked Germany. It was done for example on 20 October by 70 B-24s, and on the 10th by 39.
According to the diary of 322nd BS, 91st BG, an attack on Duren was planned on October 18, 1943, and ONE B-17 of this squadron took off but could not join the formation and the mission failed due to poor weather.
http://www.91stbombgroup.com/Dailies/322ndjan1943.html
Two aircraft of 401st BS, 91st BG did the same.
http://www.91stbombgroup.com/Dailies/401st1943.html
My guess will be that the plan on the 18th was more or less the same than on the 20th, when the B-17 force actually attacked Duren while the B-24 flew a diversion.
An interesting report is the mission report by 392nd BG, another B-24 unit that flew a diversion that day. You can see it there:
https://www.b24.net/MM101843.htm. It says "Succeeded in flushing up fighters. Probably succeeded in keeping enemy aircraft in that general area." I don't know how that was determined, by radar, R/T interception or visual contact, but there is no German claim for US bombers that day.
I don't know who made the connection between Roller and the B-24 loss, but the claim by Roller was listed by Tony Wood like this:
18.10.43 Ofw. Robert Roller: 10 6./JG 3 Spitfire UK-TK: 2.000 m. [Vouziers-Suippes] 13.26 Film C. 2031/II Anerk: Nr.34
It is NOT confirmed by the more recent JFV book by Prien, that gives the following information for JG 3 claims that day:
6./JG 3 Fw. Johannes Hoyer Spitfire (1) 13.26 PIQu. 05 Ost S / OG-3/6 2150 B
The more recent JFV book is more reliable than Tony Wood's files (that were written 10-15 years before, and use far fewer sources, especially hand written or faded victory lists with no first name, so involving a lot of guesses by Tony and people who helped him (like Jim Perry ... and me))
The only reason I can see to link both losses is the JG 3 claim at 1326 hrs while the MACR says the B-24 was last seen at 1325 hrs, but I am not even sure that Allied and German used the same time zone at this time.