In API 21, when using a custom font, the MaterialButton seems to be placing spacing between each letter.
The font is not the problem, as in other Views such as the TextView, the letters are intact.

Hi,
You can override the MaterialButton letter spacing to achieve the desired result with this font.
You should set textAppearanceButton in your theme to be a TextAppearance which sets android:letterSpacing to 0.
Let us know if this doesn't solve your problem or if you have any other questions.
android:textAppearance=”?attr/textAppearanceBody1”
Thanks @PawankumarPK, this solution is easier
Most helpful comment
android:textAppearance=”?attr/textAppearanceBody1”