Brush tool make a dotted line on transparent background with black color

Yesterday I was starting to work and needed a large brush to create a gradient (250-500px), I usually work on 1080p and 300dpi on transparent background.
The brush tool started creating these dots, so I tried making changes (like spacing), reset preferences, updating Photoshop, drivers and nothing happened.
The brushes I usually use are the default one, hard and soft, and if i set the spacing of the soft one to 5% I get an ugly banding effect on transparent.
When I export, the brush gradient is perfect.

PS: this bug apparently pops out only with black color.