Welcome to the Forum Milanski
Since this is a brand new KADET Kit, it could be a simple as; your new KADET just need a good initial cleaning
The Chamber, or the Firing Pin Tunnel could be full crud, right from the Factory
Both of these issues would cause the Round to either; not seat fully into the Chamber, or getting a good solid (initial) Pin Strike
The first Strike seats the Round, the second one firers it
Also, the .22lr Round itself, is the filthiest Ammo around
Some Brands are worse than others
Say you're using Winchester 555 .... Winchester (specially Winchester Bulk) are by far, the dirtiest of them all