"subsequently learnt about" is correct and is commonly used in written English.
You can use it when you want to explain that someone has recently found out something new or learnt more about a certain topic. For example: "She subsequently learnt about a new technique for resolving the issue and decided to give it a try."
The two men subsequently learned about the False Claims Act, better known as the federal whistle-blower law.
Since the golden toad spent its life underground, emerging only in order to reproduce, most of what was subsequently learned about it had to do with sex.
But given what he subsequently learned about applying for expedited passport processing in person, he said he was better off choosing the path he did.
New Orleans District Attorney Jim Garrison subsequently learns about potential links to the assassination in New Orleans.
Many of these people who supported the war — a majority of the Senate, former neoconservative Francis Fukuyama — were saying that if they knew in 2003 what they subsequently learned about the war, they would have taken a different position.
But, no matter what I subsequently learned about what any of this meant, the family legacy I inherited was not a story waiting to be made whole but the very gap between the geographical opacity of their raging passions and my own.
We subsequently learn about the un-localized novel sequences identified by AsmVar by linking each of the sequences of one individual to their closest neighbour (Fig. 4b).
Johnson, it was subsequently learned, has signed a new three-year contract, and shows regret about his not-so-great return to coaching with the Dolphins.
Subsequently, we learned about the SA-6, which came from a site we were targeting at the same time".
Subsequently, we learn about some typical topologies of distributed memory systems and network architectures.
