Workfront functionality question for tasks where there is a predecessor identified but then task completion date is modified to have a task constraint of "Must start on" or "must finish on" , then task showing as "At risk"

Hi All - wondering about the functionality of this scenario... we have a schedule with predecessors and task constraints of "as soon as possible", but in the generation of the schedule we find we can modify some tasks to happen on specific dates, so we change those tasks to a specific date and task constraint of "must start on" or "must finish on". The Progress Status of that task then typically flips to At Risk, even though it is a date later in the future. Is this because the tool still sees that there is a predecessor identified? Do we need to delete predecessor when we make those types of manual changes?

Thanks all!