So, even though, they had those elections where Netanyahu won convincingly, they still may have more elections? And it could be damaging per the legal status of the investigations against him because they have more time to press charges.
In the recent election Likud won 35 seats in the Knesset and Blue and White also won 35 seats in the Knesset.
President Rivlin chose Netanyahu (Likud) because in consultation with Knesset members it appeared Netanyahu had the best chance of forming a 61 seat majority government. Historically, if a government is not formed, the President has selected another member to try and form a government. This is how Netanyahu assumed the premiership in 2009. Livini of the Kadima party was unable to form a government and the President then selected Likud (Netanyahu) to do so.
Netanyahu, himself, called for new elections and pushed the vote in the Knesset to prevent Rivlin from selecting another member to form the government and serve as PM. This is unprecedented.
During the period between now and the new elections Netanyahu retains the PM chair, albeit without a parliament.
New elections will not affect the "legal status of the investigations" against the PM. There is a meeting with the prosecution, postponed at the PM's request, scheduled for Oct 2 and 3. This is the last step before a formal indictment(s), if issued. With the new elections scheduled for September 17, Netanyahu, assuming Likud wins the majority of seats in the Knesset, may not have the time to form a government and pass his much needed immunity law shielding him from indictment while PM.
The passage of this law, quite unpopular in Israel, would, in all likelihood, weigh heavily in the formation of another government headed by Netanyahu.