Between January and August last year, the number of H-1B petitions increased by 3 percent compared to a year earlier, but the jump in RFEs was 45 percent, data from USCIS show.

This year, the number of applicants for H-1B visas decreased by 9,000.

"My lawyer just sent a checklist with requests of 15 additional pieces of evidence, which even asked our company to provide the transcript and degree certificates of all previous employees in my position," Yang said.

According to Fang, the information being sought in the RFEs includes details of wages being paid to the applicants, proof of skill sets to ensure the workers truly are engaged in a specialty job and details of why the company needs a master's degree — or higher.

"The higher-level scrutiny of H-1B visas is one of the indicators of Trump's restriction on immigrant visas," Fang said, indicating the changes were part of Trump's directive to federal agencies to implement a "Buy American, Hire American" strategy.

"I think this year, the scrutiny will only be more strict and intense," Fang said. "Surely it will have a very negative impact on the Chinese students and workers who are willing to stay in the US and on US companies who rely on special skilled foreign workers."

Amanda Chu, an office manager at a Chinese company, said the increased uncertainty of H-1B approvals is "making trouble" for her company's recruitment.

For fiscal 2019, Chu's company sponsored four H-1B visas. None has received approval so far.

"Our business mainly targets young Chinese students who are studying in the US. So, our employees should be someone like our customers — speaking fluent Mandarin, well-educated, and deeply understand the Chinese culture. Those good candidates are usually H-1B visa holders or appliers from China," Chu said.

H-1B sponsorship also contributes to the staff's loyalty, said Chu, who has eight years of experience in recruitment.

"In terms of work efficiency, H-1B visa holders are usually more stable workers than green card holders and US citizens. For instance, recent graduates are usually more productive and hardworking when they learned about possible sponsorship for their positions. They will try their best to contribute to the company to fight for the sponsorship."

The unpredictability and restrictions on working visas have also created anxiety, uncertainty and fear within the international student community, especially for those who are willing to work in the US after graduation, or just recently graduated, like Yang.