Duration not having custom values, only presets.

Ver. 57.1.2, when I try to change the value of duration in prototype view custom values aren't allowed. Only the presets 0.2, 0.4, 0.6, 0.8 and 1s; the value can be deleted but it only accepts one character. Re-installed xd, changed to previous versions, re-booted computer and opened a new file yet the problem remains.