A constant mistake done while typing fast, as generally constituted by a second capital letter after the first propper capital, making you go back and replace that letter with a lowercase letter (Unless posting casually i.e Forum Postings, Chat sites, etc. unless considered a grammar nazi). Constantly happens when typing reports and /or titals for various subjects.
"WHoever that is, I wish he would stop calling me."
(Double Capital Shown once)
"'The RIde of the Valkyries' from Die WAlkure"
(Double Capital Shown here twice)