Radio Buttons not highlighting as though they are selected

Question

I'm working on an android activity with a RadioGroup containing 10 RadioButtons. For some reason or another sometimes, only sometimes, when you select a RadioButton in the RadioGroup it doesn't highlight as if it's selected but through some tests I've determined that it really IS selected even though it isn't highlighted. Another odd thing that occurs is that when you select any other RadioButton in the RadioGroup and then try selecting your original Radio Button (the one that wouldn't highlight as though it were selected) it does highlight and functions as normal.

Any idea why this is happening or how to fix it? Thanks!