This has been continuing from many years and still going on as per the sources. The clash started in a bill settlement issue of Annapurna Studios. Dasari Narayana Rao made a film in Annapurna Studios but is yet to pay the bill. When good time started for him Annapurna staff reminded Dasari about the due to be cleared. But Dasari has shown his stern recalcitrance.
Then the staff sent him a Lawyer Notice. Dasari got infuriated and called on ANR saying that he made him famous with 'Premabhishkam' and many other films and why the notice was sent. ANR said that he didn't know about that and only his staff did that. Since then Dasari dropped an iron curtain between him and ANR.
After that when Dasari and ANR encountered each other in an Airport the former ignored the latter and left the place. Sources say that the clash is still going on.