Hello Sarin
You can rest assured that such a typo is not an issue at all (given the fact that all other personal data is correct).
The allowance of up to three typos, provided the name is still recognisable, is a common practice among all public transport companies in Switzerland (and, by the way, also in the airline industry where I have worked for many years).
Although the ticketing tariff is available publicly, the ticket control instructions are not, as they also contain confidential subjects. However, what concerns typos, they say:
In the case of obvious, slightly incorrect personal details (typing errors in individual letters or digits), the e-ticket can be accepted without subsequent payment of the fare or surcharge.
Simply enjoy the travel and let me know afterwards, how it turned out. I am sure not many will even recognise the typo 🙂
Does that answer your questions?
Kind regards,
Roland