In short, some random users may have an issue with these designs that share one specific articulation, and the tail snaps off in pieces after printing. Especially when scaling down the models.
According to the total downloads and number of reports, it is a very small group of users, like 0.5 %.

I've been gathering as much info as possible from those reports and I found some common factors that lead to disaster:

• Small Scale: Scaling down makes it worse.

• Large nozzles: Printing with 0.6 mm nozzle or larger makes the slicer to smooth thin geometries.

• Curling: Usually due to poor cooling or bad filament.

• Filament shrinkage: And this is the key factor and the last I've discovered. Some filaments have a huge shrinkage factor, which is not noticeable for standard-sized parts, but becomes a huge issue for certain small geometries like this articulation.

For those of you having this issue, here you have some tips that I've tested and work, all of them intended to keep the original articulation shape unaltered:

• Not scaling down.

• Change the wall generator ("Classic" ←→ "Arachne").

• Slow down overhangs. The slower, the better. You can test it progressively.

• Reduce "Outer Wall" acceleration.

• Tune the "Pressure Advance" parameter.

• If your slicer has this setting, enable "Slow down for curled perimeters". You might have to disable "Classic mode" on "Overhang speed" for that setting to show up. This is a huge change, because it also slows down inner perimeters on overhangs.

• On filament settings: Filament → Cooling tab → "Cooling Overhang Threshold" to 25%.

• Watch out for cooling. Enclosed printers usually need to be open when printing PLA.

• Increase the "X-Y compensation" in small steps, like 0.05 mm (also called "X-Y Contour Compensation", or "Horizontal Expansion").

• Try a different filament.

With this tips I've been able to get successful prints even at 50% scale!

For testing, I suggest printing in single color to save time and material, printing just the tail, or using this test file that I've created to measure the shrinkage: Articulation Shrinkage Tester

(The real number can't be achieved because the nozzle diameter already cuts off the spiky end of the pin, but a difference of around 5% should be good enough for a reliable articulation).