The Build Back Better bill recently passed by the House of Representatives could stall in the Senate for months, NBC reported Wednesday, potentially delaying an expanded EV tax credit.

Senate Democrats are preparing to kick the Build Back Better bill to 2022 because leadership doe not believe it has enough votes to pass it, the report said, citing four anonymous sources familiar with planning in Senate Majority Leader Chuck Schumer's office.

As with much other recent legislation, Senator Joe Manchin (D-W.Va.) is believed to be a hold out, and some negotiation is still needed on the Senate version of the bill, according to the report.

2022 Chevrolet Bolt EUV

2022 Chevrolet Bolt EUV

The EV highlight of the bill is an expanded tax credit of up to $12,500 for vehicles manufactured domestically in unionized factories, something the White House said in October would make it through Congress.

Automakers with a presence in union-blocking states have spoken out against the union-made bonus, while the United Auto Workers and environmental groups have rallied for it.

And Tesla CEO Elon Musk earlier this month said that the government should be a referee, not a player on the field. Tesla has benefited from substantial government subsidies in the past, and Musk's SpaceX subsists largely on government contracts.

2022 Chevrolet Bolt EUV and EV production starts

2022 Chevrolet Bolt EUV and EV production starts

Musk also advised to can the whole vote and not pass an expansion of the tax credit—even though it would benefit Tesla. The automaker no longer qualifies for the current EV tax credit but might qualify for some amount (for certain vehicles, at least) under the proposed revamp.

As Politico outlines, the EV credit itself also faces some procedural barriers—potentially related to budget. It's also worth noting that the Chevrolet Bolt EV and related Bolt EUV are the only models that currently qualify for the union-made bonus.

Meanwhile, Canada is considering steps to align its credits for EVs with the United States. Prime Minister Justin Trudeau believes this will help head off a trade dispute, as the Canadian government views an expanded U.S. tax credit as amounting to a tariff on Canadian-made vehicles, Reuters reported Monday.