Weird issue with UI

I’m having some weird issue with custom UI button. Take a look at this menu when not in play mode:

Everything looks good right? Now when I hit play button:

The button rotation is off and also there is a white dot on the button corner. I was having same issue before with the audio mute button but after a while it fixed itself somehow. Maybe this is a bug??

Are you using sprite atlas?

Update: After wasting time with this issue for 4 hours I have filled a bug report and the developers confirmed that this was indeed a bug. For the time being I solved this issue by creating an new project and re-importing everything from the old one.