"I've tried to catch the state of the webchat on validation -> start chat button pressed and validation with error."
What validation/what input fields?
Did you create a Custom Chat Registration Form with your own Validation on certain fields? If so, that's where you will catch the validation error (for the field(s)).
There are no events generated on WebChat/WebChatService if some fields are not validated.
"WebChat called the command: WebChatService.restore"
This is a WebChat command which is invoked automatically at several stage of the WebChat plugin, checking some values in cookies.
Its purpose is to check if a chat is ongoing (e.g. after a user refreshes the page, after the user moves from one page to another with the Genesys Widgets enabled on both, ...) and if so, to try to reconnect automatically to this chat session.
It is not an Error indicating an issue. It is just the normal output if no chat session was on-going and therefore if there is nothing to restore.