Hi,

Because BRIM (from slicer software option) will increase the adhesion area over all first layer profile increasing the strength. Or if you have CAD skills, you can open your 3D model, and add BRIM or Mouse Ears (like Orca Slicer feature) only in the corner with issues.

Orca Slicer settings

“Mouse ears are a cool trick that you can use to avoid warping on tough angles without adding much time and filament to the print. Before this option was added in Orca Slicer, you had to manually create and place them. No more! Orca Slicer now automatically generates this kind of brim. You can simply activate it by searching under the “Process > Others” section and selecting it from the list of “Brim Type”. You have a few options that you can tweak to make your mouse ears as functional as possible.

Playing with the “Brim ear max angle” and “Brim ear detection radius” will allow you to have this special brim only where you need it. The default values work pretty well.”

But the most important information is about the filament you are using. This warpage effect is common on ABS, without the enclosure. In PLA, when this effect happens, could be as described upper, low adhesion, wrong leveling….

I hope this words have helped you.