This is most likely a lack of coverage in the area, ADS-B Exchange does not filter any aircraft.
A year on still the same situation.
Today (4/2/2026) fake D-AGLO flew MUC-ALG:
Edit: Seemingly a copy of 7T-VJJ AH2779 on 02/02:
The last ADSBex-position 36.794, 3.390 fits exactly with the last flying position of the FR24-csv-download at 36.793587, 3.389925 .
Replaying its take-off in MUC shows it appearing on ADSBex just when A320n D-AINI lands:
It takes off, and then E195 I-ADJU lands, followed by Oman AF C130 506…
Fortunately, we have a live stream at the runway…showing no Global Express at all…
You should have seen it in the background when the A320 landed around 1:10:40.
Focus is then on a LH A350 in the 100y-colours, the Dolomiti E195 is mentioned at 1:12:46, just visible at 1:13:13 and then the C130 touches down at 1:13:55…no mention, video or sound of D-AGLO taking off.
Acc adsb.lol and airplanes.live the real aircraft last flew LBG-MUC on 28/01 and has not flown since. On ADSBex however it flew LUX(!)-YUL on 29/01 (crossing the atlantic ~half an hour faster that you would expect with the speed before and after loosing reception over water), YUL-DCA on 31/01, YUL-BOS on 01/02, and BOS-MUC on 02/02.
The YUL-DCA-flight is a copy of C-FJZL, flight AC8823 on 30/01:
The BOS-MUC-flight is a copy of D-AIXD, flight LH425 on 02/02:
Horizontal and vertical path are identical, speeds and times are different and sometimes unrealistic.
Everytime the fake aircraft flies on ADSBex indeed it shows “D1” under Stuff - Category, on the few remaining real flights it is “A3”.
Last week we saw some fake inserted data of both USAF VC-25’s and a VC-32A over Florida. I cannot review that whole flight but it seems only one receiver feeded that rogue data….but when fake D-AGLO flies it mostly shows several (4,5,6+) receivers following the aircraft… 
This all cannot be explaned by a lack of coverage or a faulty transponder. My own SBS and several other sites including FR24 (although anonymously) show the aircraft concerned correctly. Adsb.fi and planespotters.net however are also affected…could it be a hack of the feeder-software?