Session expires often

The last few days (I think since Saturday 21 March) I get automatically logged out very often during navigation.
On the login page if I want to submit the form by clicking the “Log in”-button, following message is shown on first try:
Your form session has expired. Please submit the form again.
After second click on the “Log in”-button the login is successful.

Never heard of this bug before. Have you tried clearing cache? That often helps with these kind of things.

I tried clearing all browser data (incl. cookies) 2 times. The problem still appears.
I’m using the live version (not the beta), Chrome (Version 80.0.3987.149) on Windows 10. I’m user for 11 years now. The last years I use the page nearly every day but never had this problems before.
It seems that the problem happend also to other users in the past:

@Marijn, any idea?

Problem seems to be gone. The last few days everything works fine.