fkbnsieve v1.3 (mtsieve 2.0.6) works, but seems very slow compared to when I used it before. The p=3 step is running very slowly even with c-ranges of a few million only removing a few thousands factors per second.

Code:

fkbnsieve.exe -c 1 -C 1000000 -P 400000000 -s "1*2^65+c"
Primes tested: 21336332. Factors found: 972437. Remaining terms: 27563. Time: 48.53 seconds.
fkbnsieve.exe -c 1 -C 2000000 -P 400000000 -s "1*2^65+c"
Primes tested: 21336332. Factors found: 1944946. Remaining terms: 55054. Time: 190.56 seconds.
fkbnsieve.exe -c 1 -C 4000000 -P 400000000 -s "1*2^65+c"
Primes tested: 21336332. Factors found: 3889879. Remaining terms: 110121. Time: 758.98 seconds.
fkbnsieve v1.1:
fkbnsieve.exe -c 1 -C 4000000 -P 400000000 -s "1*2^65+c"
Primes tested: 21336328. Factors found: 972437. Remaining terms: 27563. Time: 1.73 seconds.

This last one taking 758.98s takes only 1.73s in fkbnsieve v1.1 (mtsieve 1.8.4)

I'll just use fkbnsieve v1.1 for now, but I wanted to report it in case it is a bug.