Some threads have lost formatting. Many seem OK.
If a post of YOURS allows you to edit it; simply open to edit then save. Seems to work so far.
You may want to do this for your multiple posts in a thread so they are readable.
Some of YOUR old posts at this time to not allow you to open for edit, the icon is not there.
Posts by others in the thread would require those post owners to fix.
[I am also noting that attachments seem to be missing. Pix of posted lab work etc.]