The prettiest benchy I’ve seen... until  

RE: The prettiest benchy I’ve seen... until

My money's on your part having come loose from the print bed near the end.

Proper cleaning and handling practices are a must:

http://projects.ttlexceeded.com/3dprinting_bed_adhesion.html

http://projects.ttlexceeded.com/3dprinting_bed_cleaning.html

(especially point 6 works wonders for many)

RE: The prettiest benchy I’ve seen... until

Yes, both the bench and the skirt were loose and in different parts of the bed. 

And subsequent test prints the first layers aren't sticking at all really, even though I am wiping down with IPA each time. 

I will try Dawn before the next one. 

RE: The prettiest benchy I’ve seen... until

I think the chimney was overheated. Could be to fast (low layer time because smallest part of the object), to hot or to less cooling.

RE: The prettiest benchy I’ve seen... until

@lichtjaeger

it is straight off the USB drive that shipped with the printer, wouldn't  it be sliced/setup with the mini in mind though?

RE: The prettiest benchy I’ve seen... until

Then tell us more. Did it came loose? What filament did you use? Is the printer also in an "out of the box" state or did you do a modification (other nozzle for example)?

RE: The prettiest benchy I’ve seen... until

@robrob

I had what look like the same issue with one of my first Benchys.

For me it was the issue that my z-layer was to high and that it did not stick to the sheet. First picture is the on the failed, second it work really well

I actually lowered the Z a small bit more since then.

See my post on the topic here:

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/unofficial-prusa-mini-wait-thread/paged/114/#post-194410

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/unofficial-prusa-mini-wait-thread/paged/115/#post-194505

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/unofficial-prusa-mini-wait-thread/paged/115/#post-194530

Hope it helps