Q: Why is my cursor in the wrong place?

In both Mail and Safari, if I type text and then go back to edit it, my editing does not take place in the spot where I place my cursor, but often 4 or 5 characters behind (even though the cursor is still in the right place). I had this problem in Yosemite in Mail, but this is the first time I've noticed it in Safari as well.

This does not occur in all situations. For example, my editing works perfectly here, but if I open another tab and post something in Facebook, it will be off.

Not sure if it has something to do with the default font or character encoding or what, but it's eating up time! Thanks for any help. - Jay

This is on a brand-new Macbook Pro 13" with retina and dual displays.