My first guess would be that the culprit is the annoying “stuck key” syndrome.

If the {dashed slur metatool}s triggering key is stuck, then you will get a dashed slur, no matter what smart shape you are trying to enter.

A key on the computer keyboard can be stuck, physically or electronically.

If the key is physically stuck, then you can probably see it. Try tapping the key.

If the key is electronically stuck, try a computer restart.