HTTPS admin mismatch session expire due to Admin Bar?

I'm using Domain Mapping plugin to force HTTPS on admin/login and not on frontend

when mucking around in Admin and then opening tab for frontend site to see changes, the admin session expires as soon as anything is clicked or refreshed. not a problem when using https://frontend, but this is sort of problematic because need to manually enter https

I suspect this is happening because the Admin Bar displayed on frontend is registering a mismatch between HTTPS/HTTP

I'm wondering if there is any solution for this besides disabling Admin Bar completely through functions.php or plugins, - maybe even just a plugin that turns admin bar on or off via slick button or something...

anyone else experiencing this?