Sometimes, you might add an entrance animation to object to make it appear on the slide, then add an exit animation to make it disappear, then add another entrance animation to make it reappear. Most of the time, this scenario works as expected. However, in a few cases, the second entrance animation doesn't work.
This is a known issue. It depends on how the exit animation affects the transparency of the object. For example, the Fade exit animation sets the transparency to 100%. To ensure that the second animation works as expected, add an Appear entrance animation to the object (after the second entrance animation) and set it to Start With Previous.