When I use scaling sizes & put a 9-slice inside of a frame, under certain resolutions either the sizes or positions seem to be a pixel off. This causes there to be "lines" through 9-slices.
In most cases, a pixel off wouldn't make much of a difference, but actually looks pretty bad in games like Miner's Haven:
... & in my own games:
This bug happens on www.roblox.com and can be reproduced by having a 9-slice in a scaled gui (& changing around the resolutions), but in case you want a setup done for you, here's a repro:
repro.rbxl (14.0 KB)
This bug started happening a few months back (occasionally), but is very frequent now.