I would first start by using an alcohol swab to thoroughly clean the charging contacts on the charging base and the vacuum, fully recharge, then test and monitor.
If the battery is isn’t getting a proper full charge during charging or is fluctuating during charging because of build up film on the contacts, the battery health will deteriorate rapidly. An unhealthy battery will also result in odd readings to the control board which may cause it to shut off mid-clean due to power fluctuations.
Once battery health is ruled out, then other causes can be considered.