A quick search for information.  Found a little bit, but that doesn't mean the twitter report is wrong.

Fast Markets on September 24th... just a week ago:

"Canadian miner Lithium Americas is developing the Thacker lithium project in the US region. But it hopes to extract lithium from claystone ore using an acid-leaching process.

The miner expected to release a definitive feasibility study on the project in the fourth quarter of this year, according to a company presentation released this month."

They are getting this from the September Thacker Pass Investors Presentation, so anything counter to that projected time frame would have to be something coming up in the last few days.

Globe News Wire on 30 July 2020 posted the following in their NR:

"Feasibility Study

The Company’s technical team and consultants continue to advance work on the Thacker Pass definitive feasibility study (“DFS”). Completion of the DFS is proceeding in parallel with the permitting process and sets out the design and layout of the Project. In response to the COVID-19 pandemic, Lithium Americas implemented strict health and safety measures which included temporarily closing its research testing facility in Reno, Nevada, and modifications on work required to complete the DFS. With significant progress to date, the Company expects to release results of the DFS in Q4 2020."

Note that it does make reference to the fact that the research testing facility ( the Reno Lab ) was temporarily closed, with the usual excuse:  Covid-19.  Perhaps, if we do see a delay in release for the DFS then LAC would pull out the Covid-19 card to justify it.  It seems that everyone is saying "Covid-19" these days to justify any and everything.  Chickens not laying enough eggs... must be Covid-19.  Salmonella in the Sprouts.... must be Covid-19.  Beans burning on the stove.... must be Covid-19.  Seriously, it is a convenient excuse so I wouldn't at all be surprised if LAC elected to play this card.

An article dated 3 September 2020 published in the Elko Daily Free Press quotes Lithium Nevada Corporation CEO Alex Zawadski as follows:

"A definitive feasibility study for the first phase is scheduled to be completed during the fourth quarter of this year, he said."

So, bottom line:  I haven't been able to find anything to confirm that reeport of moving the DFS to Q1 of 2021, but that doesn't mean it won't happen.  Maybe tomorrow will shine more light on it.       Okiedo