Strange cycle marker length

[AlexBell]

Exactly how is this possible?

[hendrix97]

Maybe you are inbetween frames with your in and out and not “on” the grid? Start & End rounds to the full frame, combined makes it round length to 1 frame less?
Just my guess

[saxmand]

Not that it’s the explanation, but are you working in drop frame? So any of the dfps frame rates?

[AlexBell]

Strictly 25. Even if I punch in new codes the error remains.

[saxmand]

Try go in and enable the subframes. Could imagine the answer lies in there.
If the start is a litter after the frame, but is round down, and the end is a little earlier then the frame, but rounded up, the total length gets round down: