The COVID vaccine was a bad example as it was manufacted on license from AstraZeneca, but the larger Indian market absolutely does this due to how the Indian Patent Act is structured.
"Section 3(d) of the Patents Act, 1970, explains that a new form of a known substance, new property / new use for a known substance and the mere use of a known process are not patentable and is not considered distinct from the known substance. Based on this principle, inventions using known substances are not patentable unless, for example, the alleged invention displays a significant increase in efficacy." [0]
Ranbaxy, Reddy Labs, and Sun Pharma all started thanks to this loophole, and it has been a massive blocker in any US-India Free Trade Agreement.
This is all open knowledge to all
players in the India market [1]. It's not necessarily a bad thing btw - it's a major reason India's Pharma and Agrochemical R&D pipeline punches above its weight, but it has an impact on US-India relations, but for other regions such as the EU, Japan, or Developing countries it doesn't have much of an impact.
[0] https://www.aipla.org/list/innovate-articles/the-global-sign...
[1] https://www.nishithdesai.com/fileadmin/user_upload/pdfs/Pate...