I have shared this simple survey with everyone.
I you try using this link in your popup, does it pass the date?
I think it should work.
In Collector tap and hold your link.
A panel will ask you what you want to do with the link, notice that the URL is shown on the Panel.
Does your URL have the correct date in it?
I think I have a solution, instead of passing a "date string" which is prone to error, we can use Arcade expression to pass the date as an epoch time value.
In your webmap.
Add an Attribute Expression
Set your date field to a Number
for your data Number($feature["FechaAsignacion"])
Configure the Hyperlink in the Popup to use the expression.
Notice in the Popup the value still is not correct. I used the Expression as Title and link text.
You also need to set the Formatting for the Arcade expression.
No Separator and No decimals
Now the Popup value for epoch time is correct.
This should pass correctly to Survey123
thanks for the question, it provided an opportunity for me to learn something new.