I believe this is a known issue for certain types of text fields, such as the Number and Date type fields. While OnTextChange won't kick in for a change triggered by the browser-specific options for the number field (such as the up and down arrows that appear in Chrome), it looks like it should kick in if:
There is no hint style applied to the text field
A different event such as OnMouseUp or OnLostFocus is used.
I'll file this thread with the main case on our end, but in the meantime hopefully this helps!