I'm a little confused as to how the transfer agreement between the NHL and the Swiss National Leagues (and their associated junior leagues) work. Per the draft board, Fabrice Herzog's rights just expired on June 1, and he was drafted out of the NLA. However, Elvis Merzļikins and Gregory Hofmann were also both drafted out of the NLA, and their rights are listed as 'indefinite.' What gives?

Fabrice Herzog played in North America and his 4 yrs would of started. It has been reported as well the Leafs have lost his rights after June 1.

Elvis Merzļikins and Gregory Hofmann have never been to North America, the NLA doesn't have a transfer agreement with the NHL. Which makes the player indefinite.

Regarding must sign by dates, this is based off of our current understanding and there may be more details that we havent yet uncovered

So, then, the current understanding is that, for players drafted out of leagues without a transfer agreement (namely, the National League and associated junior leagues, as well as the KHL and its associated junior league), once they play in a North American league like the CHL or the NCAA, the clock starts ticking on their player rights. This is why the rights to players like Herzog, Mārtiņš Dzierkals, Vasili Glotov, and Kārlis Čukste (who gets 5 years because he played a year in the USHL before starting at Quinnipiac) have expiration dates on their NHL player rights.

Does the expiration date start ticking once the player decides to play in North America? For example, Dzierkals was drafted in 2015, and he started in the QMJHL in '15 - '16, so his rights expire in 2019. If he had played in the MHL (or the KHL) in '15 - '16 and then in the QMJHL in '16 - '17, would his rights have then expired in 2020?