The Russian Direct Investment Fund (RDIF), which is bankrolling the vaccine, claimed Tuesday that Sputnik V is around 90% effective against the fast-moving new Delta variant of the coronavirus—an efficacy level only slightly below that for the original virus strain. On Wednesday, Russian President Vladimir Putin said he had personally opted for Sputnik V. And the vaccine’s belligerent Twitter account remains as hyperactive as ever.

Amid Russia’s positive news push, however, the Guatemalan government revealed on Tuesday that it had asked for a partial refund of what it had paid Russia for Sputnik V doses. A few months ago, Guatemala paid $80 million for 8 million doses of Sputnik V, but only 150,000 have arrived.

Health Minister Amelia Flores said Guatemala had given Russia 20 days to deliver the remaining doses.

Guatemala is not the only country complaining of delivery shortfalls. Last week the Philippines said the RDIF had informed it of delays in the delivery of 50,000 second doses of Sputnik V—unusually among COVID-19 vaccines, Sputnik V’s two doses are different formulations, an approach that the vaccine’s Twitter account says has been validated by positive results from mixing-and-matching the Oxford/AstraZeneca and BioNTech/Pfizer vaccines.

“The manufacturer is seeking more ways to improve and upgrade the vaccine that would be more beneficial and would be more effective in battling the emergence of new variants,” explained the Philippines’ vaccine czar, Carlito Galvez Jr.

In the past couple of weeks, Argentina and Mexico have also reported delays in receiving second-dose shipments of Sputnik V.

Meanwhile, back in Russia, early vaccine hesitancy has given way to a situation where demand far outstrips supply, thanks to the Delta variant’s rapid spread and new rules that mandate vaccinations for hospitality workers.

Production problems

As has long been reported, Sputnik V production is hampered by the need to produce two distinct vaccines; it may be as effective an approach as the RDIF claims, but it’s also a design that introduces extra complexity to the manufacturing process.

According to the Moscow Times, an independent English-language outlet, Russian pharmaceutical manufacturers such as R-Pharm and Generium have failed to release the millions of doses per month that they promised.

The Kremlin had previously promised to get 60% of Russians vaccinated by the fall. On Tuesday—the day on which Russia reported a record daily death toll of 652 people—it abandoned that target.

Fortune asked the RDIF about the situation with deliveries to Guatemala and the Philippines, and about the reported production problems.

At the time of publication, the fund had responded only about the Guatemalan issue, saying there had been no official request for a refund.

“What is being discussed are possible adjustments to supply schedule and delivery amounts throughout the rest of 2021 to ensure uninterrupted vaccination of Guatemala’s population by both doses of Sputnik V. No final document has been signed yet as talks are ongoing,” a spokesperson said.

“Another plane with Sputnik V is scheduled to arrive in Guatemala this week, with the next one coming already early next week to keep fulfilling obligations regarding the contract.”

The RDIF also has yet to provide any solid figures for its Sputnik V production and deliveries.

South African protests

While the Sputnik V Twitter account continues to promote the many contracts RDIF has secured—64 countries have signed up thus far—some regulators remain cool on the idea of approving Sputnik V.

In South Africa, for example, the Health Products Regulatory Authority (SAHPRA) has yet to approve the Russian jab or China’s Sinovac, despite a desperate vaccine shortage and a devastating, Delta-driven third wave of COVID-19 infections.

On Friday, the militant, far-left Economic Freedom Fighters (EFF) party organized a march on SAHPRA’s headquarters, threatening a protest outside the home of its chairperson if the agency did not authorize the Russian and Chinese vaccines within a week. “We not going to listen to nonsense things like that Sputnik needs certain things before it can be approved,” said the EFF’s firebrand leader, Julius Malema.

It was an event that caused outrage among other South African political parties and from the regulator itself, which said it “cannot allow political pressure to cloud a clear, science-based approach to approving health products where the safety of the public could be compromised.”

For its part, the Sputnik V team approvingly tweeted footage from the EFF march, along with the words: “Thousands of activists in South Africa demand a faster coronavirus vaccination rollout and approval of Russian, Chinese, and Cuban vaccines.”