I think this is unfortunate, but working as intended, but I'll let pkasting@ give a second opinion.

It doesn't seem that the Omnibox should save search keyword input if the internet is disconnected.

vadim@sourced.tech,

Can you please restart your browser and see if this still reproduces?  If so, please post the whole about:version information here, including the Variations: section.

thanks,
mark

Explanation: If the user has "chrome-instant" in the URL, this is likely a consequence of a feature called prerendering.  Prerender was recently disabled, so if you've picked up the config change, you probably shouldn't experience this behavior anymore.

I restarted the browser and it is still the same. Actually, I suffer from that since a long time (a year? don't remember).

Chromium	60.0.3112.78 (Developer Build) Built on Ubuntu , running on Ubuntu 16.04 (64-bit)
Revision	a06489456eeba3939f2f058a4e5bd6178e7b3bb9-
OS	Linux
JavaScript	V8 6.0.286.44
Flash	(Disabled)
User Agent	Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/60.0.3112.78 Chrome/60.0.3112.78 Safari/537.36
Command Line	/usr/lib/chromium-browser/chromium-browser --enable-pinch --flag-switches-begin --disable-javascript-harmony-shipping --enable-experimental-canvas-features --enable-gpu-rasterization --javascript-harmony --enable-use-zoom-for-dsf=true --enable-zero-copy --ignore-gpu-blacklist --save-page-as-mhtml --enable-smooth-scrolling --enable-features=ScrollAnchoring --flag-switches-end
Executable Path	/usr/lib/chromium-browser/chromium-browser
Profile Path	/home/sourced/.config/chromium/Default

I confirm that disabling "Use a prediction service to load pages more quickly" in chrome://settings/ Advanced fixes my problem and the search query remains in the omnibox.

> I confirm that disabling "Use a prediction service to load pages more quickly"
> in chrome://settings/ Advanced fixes my problem and the search query remains
> in the omnibox.
Thanks for checking.  That pretty much confirms my thought that it's prerendering that's the problem.

I see you're running a "Developer Build" of Chromium, not Google Chrome.  Sadly, that means Google cannot use its experimental framework to disable prerendering remotely (which was done for Google Chrome installs).  Prerender was disabled in the chromium binary in version 62; you're only running chromium version 60 at the moment.  Until you update, you'll have to either deal with the frustration of not having the search query in the URL when internet is disabled or keep "use a prediction service" disabled. :-(

I'm going to mark this as "Fixed" because it's fixed in later versions of chromium/Chrome.  If this problem stil persists for you after you've updated to chromium 62, let us know, thanks!