I'm playing a Sentinel in Mass Effect 1. I have trained Warp (which I got as a bonus skill), but it doesn't appear in my power wheel so I can't use it. Why is that?
Unfortunately, this is a bug for adepts and sentinels. The problem is that your power wheel has become too full so your bonus power cannot fit inside and, therefore, you lose it. The only way to avoid this is by taking a weapon bonus power for adepts and sentinels or setting your bonus power as the hot-key bonus power before you have too many others while the bonus power still appears on the wheel.