In scheduling When a high priority task is preempted by a lower priority task, is called as priority inversion and is a problematic scenario, effectively “inverting” the relative priorities of the two tasks, violating the priority model that high priority tasks can only be prevented from running by higher priority tasks and briefly by low priority tasks nearly about to complete their use of a resource shared by the high and low priority tasks.
Source: https://en.wikipedia.org/wiki/Priority_inversion