Neymar was told to "focus on his football" by a member of Barcelona's coaching staff amid a disagreement with assistant manager Juan Carlos Unzue.
That's according to Mundo Deportivo (h/t Marca), with Unzue "said to have made a few tactical points to Neymar that led to a rising tone over the disagreement," at which point another member of staff "felt it necessary to intervene."
As a result of the disagreement, the Brazilian "remained unhappy" and the argument was heavily discussed in the dressing room after training.
The incident took place ahead of Barcelona's 4-1 victory over Villarreal, in which Neymar scored and produced an outstanding performance.
Neymar has had a largely excellent season and notched 16 goals and 24 assists in all competitions.
However, as noted by ESPN FC's Dermot Corrigan prior to the Villarreal match, his recent form hadn't been as sensational:
Barcelona boss Luis Enrique was full of praise for the forward after the game on Saturday, per football journalist Rik Sharma:
As well as opening the scoring, he also created two chances, completed seven take-ons and won three tackles, according to Squawka.
His most impressive moment contributed to Barca's third, when he deftly flicked the ball over a Villarreal defender on the byline before picking out Luis Suarez with an accurate cross, with the Uruguayan winning a penalty by striking the ball into Jaume Costa's arm.
Nevertheless, football journalist Rafael Hernandez agreed with the sentiment expressed in the training ground clash with Neymar:
That does not appear to have been a significant issue this year, with the 25-year-old back to producing some of his best performances on the pitch.
Barcelona will be hoping that continues for the long term, though they equally need to ensure they don't risk upsetting the player further. As such, their communication with Neymar will remain of vital importance.