I don't wake up with a morning erection but i sometimes wake up in the night with erections, why dont i get the infamous morning wood?

If all else in life: If life is going fine, without psychiatric, hormonal, or blood circulation issues affecting erections, then it doesn't matter much if a person gets normal erections at particular times of night but not at the time he wakens to arise in the morning. However, too much worrying or overthinking of one's erections and penis may lead to anxiety... as in performance anxiety... when an erection is needed.

Erection problems : Your sleep cycle or body's cycle may be affected. Often obese patients often have sleep apnea which causes a lack of deep sleep and stress while sleeping. Often changing the times you sleep can contribute to this.