He wasn't loaned. He signed with Jokerit of the KHL. Two years.
But Habs still qualified him in case he returns, they keep his rights. If they want to keep his rights next year, they will need to qualify him again.
It was similar to Hudon last year, who signed in Europe, but Habs qualified him to keep his rights. They still let him go a year later. But just in case, they retain his rights.
AFAIK, they didn't let go of Hudon's right. He became UFA due to age.
This will happen on February 06 2024 for Leskinen (unless they let him go before that).