带有安全条目的UITextField，在编辑之前总是被清除

I am having a weird issue in which my UITextField which holds a secure entry is always getting cleared when I try to edit it. I added 3 characters to the field, goes to another field and comes back, the cursor is in 4th character position, but when I try to add another character, the whole text in the field gets cleared by the new character. I have 'Clears when editing begins' unchecked in the nib. So what would be the issue? If I remove the secure entry property, everything is working fine, so, is this the property of Secure entry text fields? Is there any way to prevent this behaviour?I am having a weird issue in which my UITextFie