That was an easy yet difficult thing.
Lord Huai was allowed to return to the capital, because he was the Lord, but the Heir did not like it that Lord Huai returned at this moment.
One of the reasons why the Heir did not like it was because he had not yet gotten everything arranged and found a firm spot for himself, and Lord Huai's return was definitely going to hurt his plan.
In the court, many important ministers conventionally assumed that Lord Huai, who was born from the Queen, should be the rightful heir for the throne.
If Lord Huai was absent from the capital for long, then they could just reveal to the conventional ministers that Lord Huai had no intention of taking the throne, so they could change their mind. However, since he was back in the capital, the Heir's message to them would not work. That was why he got very anxious.
