Microsoft edge spell checker does work but has a short time delay before it works, so if I start typing it works after a short time, so that explains why it was random or perhaps only works after a specific number of words/characters have been typed, but on occasions it has not switched on at all so my definition of random is probably still correct. It could be an connectivity problem as I find the edge logs me out a lot and I have to keep logging back into community page so perhaps better using google chrome, also my computer using a light windows version (cheap under £200 computer) that can have problems with some applications, some will not run at all.
The extension I added Microsoft Editor (spell checker) will not work unless logged into Microsoft but I use a local log in on my computers so that is an issue only solved by having a Microsoft login for the computer selected, perhaps that is why edge does not always work properly and does crash or close by itself sometimes.
Also the edge although updated is different to the edge on my other computer, displays differently as it is not incorporating the chrome properly.
I may consider a Microsoft computer log in, used to use it but had problems with recovery once, would not accept the Microsoft password and had to rebuild windows from backup disc/flash drive, hence why I now use a local login now.
At least I can get it working now mostly, the issue happened after updating browsers and is not connected to the postings page and will use chrome.