You're not following the logic on how and when the popup code is triggered. The script onpage load, must detect a local/session/cookie is stored from previous page load before it fires the popup script.
The code I provided above does just that. Below is simplied version.
1. Page 1 loads, Sets a session/local/cookie.
2. Page 2 loads and sees if that session/local/cookie exists, since GoogleBot doesn't save that local/session/cookie data across page loads, the conditional if statement is not met and the popup isn't rendered.
if (dataForPopup) will never be true for a GoogleBot, so the code within the if statement will never execute.
[CODE=javascript]$(document).ready(function() {
let dataForPopup = sessionStorage.getItem('data');
if (dataForPopup) {
// open popup Googlebot cannot store session storage so this isn't performed.
}
sessionStorage.setItem('data', 'dataArr');
});[/CODE]
