The bulk viscosity of interacting strange quark matter in a strong external magnetic field B_m with a real equation of state is investigated. It is found that interquark interactions can significantly increase the bulk viscosity,and the magnetic field B_m can cause irregular oscillations in both components of the bulk viscosity, ■(parallel to B_m) and ■(perpendicular to B_m). A comparison with non-interacting strange quark matter reveals that when B_m is sufficiently large, ■is more affected by interactions than ■. Additionally, the quasi-oscillation of the bulk viscosity with changes in density may facilitate the formation of magnetic domains. Moreover, the resulting rmode instability windows are in good agreement with observational data for compact stars in low-mass X-ray binaries. Specifically, the r-mode instability window for interacting strange quark matter in high magnetic fields has a minimum rotation frequency exceeding 1050 Hz, which may explain the observed very high spin frequency of a pulsar with m=1122 Hz.