When messing around with 1.13, I noticed that the FPS in the F3 screen would always be 59 at most although the Max FPS setting is set to 60. In 1.12.2 it would reach 60 like normal. If I set the max FPS to 61 in options.txt, the FPS will be at most 60. If I set it to 70 with the slider in video settings, the FPS will be at most 69.

I don't think this is intended, having the FPS in the F3 screen always be one lower than the max FPS setting.