He can't afford to have an ego clash with a star like Mahesh Babu at any stage of his career. Hence, after everything between them looked really bad, he decided to apologize and end the matter.
Mahesh Babu gave him ample amount of time to come up with a script but he couldn't. Hence, Mahesh looked for other options.
As a communication gap arised betweeb them, someone else started reporting it as a big clash between them and the word spread.
Mahesh in a very soft manner decided to end the matter by praising his work and now, Sukumar is mending all the gap between them to get another chance to work with him, it seems.
He flew to Maharshi sets in Chennai to meet him and once they talked, they clarified everything it seems. Still, there is no sign of them collaborating again.