Yes, the Minnesota GOP is involved in supporting two marijuana legalization parties - Legal Marijuana Now (LMN) and Grassroots-Legalize Marijuana (GLM).
While many of the candidates are longtime cannabis reformers, a number of them are running as a ruse. They’re Republicans pulling a dirty ballot trick.
Many of these candidates have no prior experience in electoral politics and have done nothing previously to help end cannabis arrests. Some have little intention of legalizing marijuana, now or ever. Some have openly admitted that they’re running primarily to siphon off Democratic votes so that Republican legislative candidates will win. (Leafly, 10/20/20, emphasis added)
Post election, the GOP retained control of the Minnesota Senate one of only two split state legislatures, along with Alaska, by one vote1.
Tyler Becvar was a vocal Republican supporter who ran for state Senate in Minnesota’s 27th District as a Legal Marijuana Now Party member. ... Becvar had never before taken a public stand on legalization. But he was able to garner 2,699 votes—6.68% of the total. That was enough to unseat Sen. Dan Sparks, a Democrat, who lost to Republican challenger Gene Dornink by 1,818 votes.
That single race may have tipped the chamber to the Republicans—and killed the statewide cannabis legalization bill in the Senate. (Leafly, 5/6/21, emphasis added)
An LMN candidate even admitted directly:
Four months before Legal Marijuana Now Party candidate Adam Weeks died in September, ... he told a close friend that he had been recruited by Republicans to draw votes away from Democrats.
In a May 20 voicemail message provided to the Star Tribune, Weeks told a longtime friend that Republicans in the Second District approached him two weeks before the filing deadline to run for Congress in the hopes he’d “pull votes away” from incumbent DFL Rep. Angie Craig and give an advantage to the “other guy,” Tyler Kistner, the Republican-endorsed candidate. (Star Tribune, 10/28/20, emphasis added)
The Minnesota Democratic-Farmer-Labor (DFL) party was aware of these parties and their ties to the GOP as early as summer 2020, and filed an FEC report against weeks "for not filing a campaign finance report and dug up more than 100 social media posts in which he professed support for Republican candidates and conservative policies" (Star Tribune, 10/28/20).
I can only assume that because the FEC report complained only about disclosures, not somehow being a "sham candidate," that there was no legal way to block the GOP support of LMN and GLM.
1: The tally is 34 GOP - 31 DFL - 2 Independent. The Independents left the DFL recently. While they may not have legalized weed, the point is the ruse tipped the balance in the state Senate.