Looks like you have once been running a DIFFERENT timer script from a different source.
The latest code update V0.1.6 from Kai Krause from 03/28/2018 fixes the timer user script (pausing does not work that great anymore, I agree). I successfully use it myself on Firefox.
Which one?
So you obviously have not even tested the above linked V0.1.6 user script???
Basically to use Duolingo or Memrise successfully you need Firefox or Chrome/Chromium, Opera or Safari like browsers.
Camilo gave on his website GitHub - camiloaa/duolingotreeenhancer: User script for a better experience when using Duolingo for his Duolingo user script the further tip of the addons Violentmonkey for Opera or “Java Script Blocker” for Safari.
You may want to re-test Chrome/Chromium, Opera or Safari if you do not like Firefox.
Yes, I agree with you (both), therefore I have adjusted my third comment and reply text: [Feature Request] Turn off the timer (web) - #6 by Thomas.Heiss
But it is up to the Memrise staff in their UK HQ to decide why they don’t want to incorporate that since years into their own web code and not to respond to any user requests (ignore all of us).
Didn’t I try hard and haven’t I given you the explanation already in my 2nd post in May 06?: [Feature Request] Turn off the timer (web) - #2 by Thomas.Heiss
Look, how far have you guys come with this thread in the last 4 months with ZERO feedback from Memrise staff?
David, MANY things on the Android app (lack of full typing support in reviews, given non-requesed letter hints, multiple-choice, no self-rating answers,…) and web portal are or have been stupid (e.g speed reviews, multiple-choice, 3-7 forced error repeats, lack of “overdueness” support, etc.).
You (and we, the community) have to accept it as it is.
NOTHING will happen here if you do not implement the code for yourself.
Anyways, as you basically need more user scripts to make the very best out of the Memrise and Duolingo web portal, the timer is your least problem and quite a few issues could (some are broken now with code module updates) or can be fixed with Tampermonkey/Violentmonkey & Co.
I am fixed to use Firefox V52.9.0ESR and Tampermonkey, but feel free to test different browsers and newer versions and Violentmonkey.
Best regards