Infinite scroll: on scrolled page, browser "back" button creates offset issues

This happens always on Chrome, and only sometimes on Firefox.

This happens on a shop page which is set as a front-page (and not on an archive page, for example).

Stock Storefront theme. Only Jetpack and WooCommerce enabled.

Video:
https://www.loom.com/share/0d3c3dad7c77472bb576df6f7c4a6655

on infinity.min.js, this line calculates the next page number:
`page: this.page + this.offset`

On a regular scroll, the types of both `this.page` and `this.offset` are `number` (see video).

But, when coming back to the page via the browser back button, the type of `this.offset` is a `string` (see video).

For this reason, instead of, for example, going from page 3 to 4, the code goes to page 13 (see video).

When replacing:
`page: this.page + this.offset`

With:
`page: this.page +Number(this.offset)`

The issue is solved.

Another issue that might be related (#17109) (also happening in Chrome and not in Firefox):
When coming back to the page via the browser back button, the page starts with the current scrolled batch and **not** loading all previous batches until the current position.

Start in infinity.min.js at the page calculation using this.page and this.offset, then reproduce the browser-back flow on a front-page shop using Chrome and the Storefront theme. Done means the offset remains numeric so scrolling advances from page 3 to 4 rather than page 13, and the reported behavior is checked in Firefox as well.

Written by the indexing model from the issue text.