Non-AJAX pagers aren't refreshless and sometimes failing to load content completely

Not easy to reproduce but if you have a pagination with 5 to 10 pages, you should see the issue. When you poke around and click on a different page in the pager, you can sometimes end up with the below URL in the browser bar:

http://site.env/?_wrapper_format=drupal_refreshless&js=true&refreshless_page_state%5Broute%5D=wJ7t7prPTLo0fYhfBdQM1r9bIdER7jQ6f4Qqr9PMYTg&refreshless_page_state%5Broute.menu_active_trails%3Aaccount%5D=bcGMzw570bHa1IU2NrJSIBlSLtoRVkoO86Eo5GjI-WI&refreshless_page_state%5Broute.menu_active_trails%3Afooter%5D=S3S_hhd8E-MjpZwYSE3NmdUydyJWz4UVYgRveLaAWww&refreshless_page_state%5Broute.menu_active_trails%3Amain%5D=kX43JQjsd9LE86xdFBr8GfqHbaxyo7fx_7FRqgLibrI&refreshless_page_state%5Broute.menu_active_trails%3Atools%5D=4oTudvb0QeYBRpFc2Ka8pjKV0IMcACKsweUtmIzQ-L8&refreshless_page_state%5Burl.path%5D=lLRzkyoSHZgK--uI-pdkxK88SDlTiM0CccK6t9qwI2w&refreshless_page_state%5Burl.query_args%3A_wrapper_format%5D=4_MiMZO6cTei9fcy072A1PUYSMRsNbnHS52XNDBfT8A&refreshless_page_state%5Burl.query_args%5D=ctmUp1woK3uRmAZplCJK2T_lXwyiZTijzelfXaw1oyY&refreshless_page_state%5Burl.site%5D=UlqO7EXbEac8dqqKBz2IF5JzHT1ttUCYos_3FgQnbI4&_drupal_ajax=1&ajax_page_state%5Btheme%5D=bartik&ajax_page_state%5Btheme_token%5D=&ajax_page_state%5Blibraries%5D=bartik%2Fglobal-styling%2Cclassy%2Fbase%2Cclassy%2Fmessages%2Cclassy%2Fnode%2Cclassy%2Fnode%2Cclassy%2Fnode%2Ccomment%2Fdrupal.node-new-comments-link%2Ccomment%2Fdrupal.node-new-comments-link%2Ccontextual%2Fdrupal.contextual-links%2Ccontextual%2Fdrupal.contextual-toolbar%2Ccore%2Fdrupal.active-link%2Ccore%2Fhtml5shiv%2Ccore%2Fnormalize%2Chistory%2Fmark-as-read%2Cquickedit%2Fquickedit.inPlaceEditor.form%2Cquickedit%2Fquickedit.inPlaceEditor.plainText%2Crefreshless%2Frefreshless%2Cshortcut%2Fdrupal.shortcut%2Csystem%2Fbase%2Ctoolbar%2Ftoolbar%2Ctoolbar%2Ftoolbar.escapeAdmin%2Ctour%2Ftour%2Cuser%2Fdrupal.user.icons%2Cviews%2Fviews.module%2Cviews%2Fviews.module&page=4

And a blank page with only this textarea (sorry for the verbose output, it's devel_generate):

[{"command":"settings","settings":{"ajaxPageState":{"theme":"bartik","libraries":"bartik\/global-styling,classy\/base,classy\/messages,classy\/node,classy\/node,classy\/node,comment\/drupal.node-new-comments-link,comment\/drupal.node-new-comments-link,contextual\/drupal.contextual-links,contextual\/drupal.contextual-toolbar,core\/drupal.active-link,core\/html5shiv,core\/normalize,history\/mark-as-read,quickedit\/quickedit.inPlaceEditor.form,quickedit\/quickedit.inPlaceEditor.plainText,refreshless\/refreshless,shortcut\/drupal.shortcut,system\/base,toolbar\/toolbar,toolbar\/toolbar.escapeAdmin,tour\/tour,user\/drupal.user.icons,views\/views.module,views\/views.module"},"history":{"lastReadTimestamps":{"45":0,"64":0,"100":0,"87":0,"48":0}},"refreshlessPageState":{"route":"YU4zL-VUZhxmmdmbOPoP6s42MqSmed67qIJpi4h9TbU","route.menu_active_trails:account":"bcGMzw570bHa1IU2NrJSIBlSLtoRVkoO86Eo5GjI-WI","route.menu_active_trails:footer":"S3S_hhd8E-MjpZwYSE3NmdUydyJWz4UVYgRveLaAWww","route.menu_active_trails:main":"kX43JQjsd9LE86xdFBr8GfqHbaxyo7fx_7FRqgLibrI","route.menu_active_trails:tools":"4oTudvb0QeYBRpFc2Ka8pjKV0IMcACKsweUtmIzQ-L8","url.path":"eiNxjezrDXolKwPtVPfAblf7AhqXd4qEiYXlfeqJiRs","url.query_args":"CZlosFvI-cfKsgjX5iIFJN8xo4eOkZ925zuoizQkj5o","url.site":"UlqO7EXbEac8dqqKBz2IF5JzHT1ttUCYos_3FgQnbI4"},"pluralDelimiter":"\u0003","user":{"uid":"1","permissionsHash":"da7cbb01c44ca1489eb22c49e3a6fefc5276b6afedebd5b1be3802561a350a25"}},"merge":true},{"command":"refreshlessUpdateRegion","region":"breadcrumb","data":""},{"command":"refreshlessUpdateRegion","region":"content","data":"  \u003Cdiv data-refreshless-region=\u0022content\u0022 class=\u0022region region-content\u0022\u003E\n    \u003Cdiv id=\u0022block-bartik-page-title\u0022 class=\u0022contextual-region block block-core block-page-title-block\u0022\u003E\n  \n    \u003Cdiv data-contextual-typeof=\u0022schema:Person\u0022 about=\u0022\/user\/0\u0022 class=\u0022profile\u0022\u003E\n  \u003C\/article\u003E\n\n        \u003Cspan\u003E\n          Submitted by \u003Cspan data-quickedit-field-id=\u0022node\/100\/uid\/en\/teaser\u0022 rel=\u0022schema:author\u0022 read%2Cquickedit\/quickedit.inPlaceEditor.form%2Cquickedit\/quickedit.inPlaceEditor.plainText%2Crefreshless\/refreshless%2Cshortcut\/drupal.shortcut%2Csystem\/base%2Ctoolbar\/toolbar%2Ctoolbar\/toolbar.escapeAdmin%2Ctour\/tour%2Cuser\/drupal.user.icons%2Cviews\/views.module%2Cviews\/views.module\u0022 \/\u003E\n"}]
(snipped)