Update not functioning anymore

[kinoegit]

I'm using latest version of ungoogled Chromium with firejail sandbox. Updates are announced as usual, clicking on name of extension formerly started update. Now clicking only opens a new tab (in background). Then nothing happens until the new tab is manually closed then update seems to be downloaded into download folder. Thats it! Nothing else happens. I can manually update the downloded extension by drag 'n drop into chrome://extensions/. The following is set:

If you are using ungoogled-chromium: You must change the flag chrome://flags/#extension-mime-request-handling to Always prompt for install. The following is unset: If you are NOT using ungoogled-chromium: Ensure the following option is checked: Extension Options (chrome://extensions/?options=ocaahdebbfolfmndjeplogmgcagdmblk) > Advanced > Always download CRX files

What I tried without avail: disabled all non relevant extensions, started update by right click 'update all extensions'