I have two mini’s a .3 and a .4 and the .3 just started doing wierd stuff on the first layer.
Both of these were printed with the exact same print settings via cura and the bottom of the right print is weird and separated. Other than that first layer everything else prints with optimal quality.
Looks like resetting the firmware back to default on my .3 fixed it.
That looks like the cooling fans on one of your printer might be cooling more than the other. ABS splitting like that is most commonly due to the filament retracting as it cools causing layer separation. If one of your printers is sitting closer to a window or vent it might cause this to happen even if the settings are the same.
Thanks for the high-res photos of the first layers; it’s good to see what a good first layer looks like.
My bet is that the Z Offset of the bad printer is too high. You can see in the zoomed version of the photo that the filament on the right seems not at all ‘squished’ into the bed. The Lulzbot assembly page on Z Offset will walk you through the details of changing your Z-offset: https://ohai.lulzbot.com/project/z-axis-offset-adjustment-LulzBot-Mini/maintenance-repairs/
It makes sense to me that re-flashing the firmware fixed the problem: Re-flashing sets your Z Offset back to the default value.