Accessibility not reading correctly (need to press the down arrow)

Hi,

I have just published a new course and it is not reading correctly.

It says the slide is blank and only starts reading when I click the down arrow, then it will ready 1/2 a sentence and when I click down again it will read some more.

I tested this course a month or so ago and it was fine, so I'm guessing it's the update?

Many thanks,