In 2017, the NBA considered a rule that would have banned teams from trading swap rights in between seasons in which it owed its first round pick outright, sources tell Zach Lowe of ESPN. 

The push was in response to the trade the Brooklyn Nets made with the Boston Celtics in 2013 that resulted in Jaylen Brown and Jayson Tatum ending up with Boston.

The rule would have been a continuation of the Stepien Rule that prevents teams from trading first round picks in consecutive years. 

The rule never got far off the ground, but for several years teams became more conservative in trading away picks.