The problem is when changing the length of the seasons.

If you increase the size of the seasons in the world settings (for example: from standard to long), then the rifts in the caves (and by the way, with lunar rifts, the same problem) will not appear after five days as it should. Only after the appropriate time (20 days, i.e. from 1 to 20 (approximately)) will the faults begin to appear.
I will give a small example. You play in the spring on day 44, defeat Reanimated Skeleton (Celestial Champion), activate the rifts and after playing a little (not exceeding 5 days from activation) decide to lengthen your seasons. Change in the settings from standard to long and your season has increased. After 5 days, no cracks appear. They will start appearing around before the countdown to the end of spring 20 days (approximately), i.e. you have 46 days before the end of spring, you have 24 days left and only on day 62 will faults appear (I can’t say for sure about the days given).
Personally, I waited a very long time for the rifts to appear after defeating the boss and activating. As a result, I had to activate it myself in the settings, and only after that they began to appear. Then I turned it off and they also continued to appear (apparently due to the activation of the rifts after defeating the boss).