The problem most likely is that the touchscreen controller has no battery buffer for its clock, i.e. it forgets the time after each poweroff. When it boots, it tries to connect with a time server via its network connection, but if for whatever reason it cannot get the time server’s response, the clock will be off - 1970 is the old Linux/Android standard value. So, make sure that the printer can connect to some network, and that it can query the internet for an NTP server.
I recently sniffed on the network traffic of the touchscreen - details here: [GUIDE] How to install apps on your Snapmaker 2.0 LCD - Access Android part of LCD - #16 by Hauke
EDIT: Sorry, overlooked that this is for Artisan - I cannot vouch that what I write is true for Artisan, but I’d assume so.