I have seen this happen April 1 for the days of the week that were in March, and again on May 1 for the days of the week in April. It appears to only be a display bug on the week where the month changes and it only happens after the first of the new month.
Just an observation. I am sure it will get fixed eventually.
This observation is consistant with what happened on my klok too.
The cascading doesn’t seem to happen until the 1st.