Week numbers stopped in 2021

My calendar simply doesn’t continue the week numbers in 2021. I can see them in 2020 until week 53, but beginning from week 1/2021 the are missing. Looking at January 2021 i can see “week 53 of 2020” for the first line beginning with dec 28. but in the following lines there are no more week numbers.
Any ideas?

I’m not seeing that.

What version of eM Client are you using? If it is not the most recent in the Release History, can you upgrade and see if there is any difference.