Fred

You probably mean version 3.12 where the bug had arisen.
I was still working with version 3.11.8 (private cloud) until now. It appears that the bug was fixed in version 3.13 for me. OK, there did exist a solution to the problem for version 3.12 such as changing the language setting of the browser and changing the Ninox language to Englisch instead of (auto), but for me this was not a good solution to notify all my customers, who were also using different computers in different places with different users. As a result, I had to skip the full release of the new version 3.12 until now.... Maybe a solution for you guys is to reverse the browser and Ninox settings you had done for version 3.12?

I may not be searching correctly, but I have not noticed anyone else saying that the 3.13.1  enhancement "Editor in rich text field" has not materialised (as it was meant to in the Public Cloud web that I use). The very limited old editor is stubbornly there. I was eagerly awaiting the feature "Hyperlinks: A dialog box to specify the URL and display text, with links that open in a new tab" in particular, and thatg alonside the other RTF enhancements were going to be a huge bonus to anyone trying to print decent-looking text-based management reports. 
I contacted support about this over a week ago, and got the usual "I have been able to reproduce both of the issues in question. I will pass them onto our developers to make sure they are logged as bugs, and  get back to you shortly with an update."
Way back in years, I recall an earlier introduction of an improved RTF field editor, but it was quickly withdrawn as it did not work. 

Mel Charles said:
When I double click a cell on a main table - it goes into edit mode as expected. but i no longer see the little form slide in arrow thingy that you could click to exit edit mode and slide open the form - Now I have to clock out of the table and load another table then go back or log out !

I wasn't too interested in the latest version because I only use the Mac app. It's finally out and I can do some testing. For some reason the "slide in arrow thingy" or .hud-right-lash div has been made a child of (moved inside of) the .hud-menu div and they set the top property to 48px so it doesn't really show up (you can see a shadow of it underneath the last record icon). If I set the top property to 0 it shows up and is functional, but it covers most of the last record icon.

The fields Date, Date + Time and Time, don't work. Can't add data in this fields.

It is absurd that version 3.13.3 for Android comes out and the Dates, Dates + Time and Time fields do not work, it is not possible to include data in those fields.

poor quality in this version.