Number pad on lockscreen disappears, then reappears a couple seconds later. Why?

[Android Central Question]

With my Verizon LG V20, every time I re-boot my phone, the number pad appears and I begin to enter my 6-digit lockscreen code. The number pad then disappears for a couple of seconds before reappearing. I am then able to complete the lockscreen code and unlock my phone. But this disappearing act is driving me batty. Does anybody know what is going on? I am not using any 3rd Party lockscreen apps, but I do have a wallpaper installed. But, it has been doing this from the beginning.