Disappearing Text on Number field with Value=Underscore

I have a text field that only allows entering numbers. The issue that I am facing anytime time I type the 5 digit number into the field the underscore default value clears out all of the numbers except for the last number upon clicking on anywhere on the screen.

Below I have included the section that I am having an issue with take notice to value="_____ underscore">:

<input id="ctl00_ContentPlaceHolder_customZip" name="ctl00$ContentPlaceHolder$customZip" type="text" size="20" class="riTextBox riEnabled textXSmall" value="_____">

Here is the code that i am using to select the browser page > select the pop up window > select field > enter data on the field:

{

“Name”: “TEST PAge”,
“CreationDate”: “2021-6-24”,
“Commands”: [
{
“Command”: “selectWindow”,
“Target”: “title=*Search Engine”,
“Value”: “”,
“Description”: “”
},
{
“Command”: “selectFrame”,
“Target”: “ProximityWindow”,
“Value”: “”,
“Description”: “”
},
{
“Command”: “XClick”,
“Target”: “id=ctl00_ContentPlaceHolder_customZip”,
“Value”: “”,
“Description”: “”
},
{
“Command”: “type”,
“Target”: “id=ctl00_ContentPlaceHolder_customZip”,
“Value”: “78746”,
“Description”: “”
},
{
“Command”: “XType”,
“Target”: “id=ctl00_ContentPlaceHolder_customZip”,
“Value”: “${KEY_SPACE}”,
“Description”: “”
}
]
}

Can you please record a video of this issue?