Dear @mariagdelamo
Do you have any third-party plugins installed or CUSTOM JS code? Is it possible to deactivate it for a moment to see if the problem remains?
you probably set a caption by selecting the carousel element and then clicking "edit caption"
0_1576689592063_Screenshot 2019-12-18 at 18.19.37.png
the option only hides the per-slide captions. these are the ones you set when you edit a carousel and set a caption per slide:
0_1576689548855_Screenshot 2019-12-18 at 18.18.51.png