At first, I thought that this is my local problem, but then I noticed that other forums and websites do not show the same behavior - and the DT community did not either, some time ago.
But right now, each new tab for this community in Safari requires me to login again!
Yes, each time.
But I also used them when I wrote last time (soem weeks ago or so) and never saw such an effect.
I now removed “website data” from Safari preferences / Privacy but I did not get logged out. It seems that this does not remove cockies … going to check further
At least one of the products you named above is regularly updated with new definitions, so the fact that something worked previously is not necessarily a sign that one of those pieces of software is not responsible.