Is this one bugged or am I missing something?
Orbital period may refer to the star it is orbiting, while the tidal lock may be towards another gas giant. I guess?
S
Aster is only orbiting its star and the star is solo as well.
As already mentioned, tidal locking only reflects that the body is in a fixed rotational ratio compared to the body it's orbiting. We are all familiar with tidal locking at a 1:1 ratio, because that's the one we are most familiar with because of the moon, but even in our solar system we have tidal locking that's not a 1:1 ratio, Mercury is in a 3:2 tidal resonance with the sun, it rotates three times for every two orbits. In Elite both 1:1 and resonance locks are described as tidal locking, you will see a lot of them once you start looking, it's not that uncommon in the universe I would suggest.
Your situation here doesn't immediately calculate down to a resonance but that's probably because we are only getting single decimal point accuracy, it looks like a 66:1 resonance as Sysmon suggests.
What you're missing here is that Merlin is considered a moon of Aster, and they are tidally locked to each other. More commonly you see binary pairs that both have the same rotational period and orbital period. In the less common case where a planet is tidally locked to its moon, the rotation period is the same as the moon's orbital period, but the planet's orbital period is still the length of its "year".