I just updated to Layouts 2.6, and the admin is now displaying errors:
Warning: file_get_contents(/home/nemametr/public_html/wp-content/plugins/layouts/vendor/otgs/ui/src/php/../../dist/assets.json): failed to open stream: No such file or directory in /home/nemametr/public_html/wp-content/plugins/layouts/vendor/otgs/ui/src/php/OTGS_Assets_Store.php on line 63
Warning: file_get_contents(/home/nemametr/public_html/wp-content/plugins/layouts/vendor/otgs/ui/src/php/../../dist/assets.json): failed to open stream: No such file or directory in /home/nemametr/public_html/wp-content/plugins/layouts/vendor/otgs/ui/src/php/OTGS_Assets_Store.php on line 63
Warning: Cannot modify header information - headers already sent by (output started at /home/nemametr/public_html/wp-content/plugins/layouts/vendor/otgs/ui/src/php/OTGS_Assets_Store.php:63) in /home/nemametr/public_html/wp-admin/includes/misc.php on line 1196
New info - if I login to the site backend in a cleanly purged/fresh cache, I don't see these errors right away. If I go to the Toolset dashboard, the errors appear, and then become persistent in the Admin. I had a colleague login to the site initially in Firefox, he didn't see the errors until going into the Toolset dashboard. So this seems like an issue internal to the plugin and the admin. It's not putting any errors on the front end, everything appears to be displaying correctly.
Would it be possible for you to do a manual reinstall of the plugin by downloading the zip file from below and uploading it to your site ? https://toolset.com/account/downloads/
Please try this and let me know the results as soon as you can.