Are you confirming you are actually ovulating with basal body temp? You can get and LH Spike without actually ovulating. It doesn't seem like that's the case here but BBT can help confirm. As the other comment mentioned, it's normal for your ovulation day to be variable.
When ovulation is in your cycle is the most variable point in your cycle so it can definitely change and everything still be normal and healthy. Do you have concerns you are not actually ovulating or just concerned the timing changed?