Recently I noted a major change in the way entries were treated when posting on this forum.
I was unable to underline text, attempting to use preformatted text was difficult at best and had horrendous results most of the time.
I began searching for the cause and it appeared to be a change in the settings on the toolbar for the text entry window.
I found that the toolbar appeared like this.
and I noted the grayed button at the far left of the bar.
I then tried experimenting since I did not recall having that switch button on the bar earlier.
What I discovered was that if I clicked on the ‘M’ there it switched the entry back to the way I had been used to for inserting preformatted text, underlining, etc.
My toolbar now looks like this and text entry is working as expected.
Note that the first has the A highlighted and the second has the M highlighted. The M gives the entries the way we have been used to and the A changes it.
It appears the change probably was due to a recent update on discourse which is the software hosting this forum.
All changes that were unexpected and the default with the change was to have the switch set to the A which altered the inputs.
I suspect this is the cause of many who attempt to paste as preformatted text where it becomes one massive group of red lines, each with a single backtick at beginning and end.