Several workers at Tesla’s Shanghai plant, its biggest manufacturing hub globally by output, said they had been awarded a large increase in their latest quarterly performance bonuses.

The workers said they welcomed the award after the EV maker had cut bonuses for many staff in the previous quarter.

Discontent at the plant emerged in April after several workers took to social media to complain about bonus cuts and appealed directly to founder Elon Musk, who said he would look into it.

Three workers told Reuters that they had received bonuses of 1.5 times of monthly base salary for the second quarter. This was higher than the quarterly bonuses – 1.2 times the monthly salary – that the majority of workers used to receive for average performance, the workers said.

The workers said several of their colleagues had received similar sized bonus increases but Reuters was unable to establish how many had been awarded a bonus hike. The plant, which makes Model 3 and Model Y, employs around 20,000 workers.

One of the workers said that his performance bonus had doubled this month on the first quarter, when it was cut to 0.785 times the month salary.

The workers said they were not given a reason for why their bonus had increased and if it was related to the previous complaints. But the move comes after Tesla delivered 247,000 units of China-made EVs in the second quarter, the highest level since its Shanghai plant opened.

Tesla did not immediately respond for a request for comment.

In May, Musk paid a late night visit to the plant as part of his first trip to China in three years. He thanked the workers for “the amazing work”, overcoming difficulties and challenges in a speech at the plant.