Corner option border error in eBook format
i'm working on an ebook in indesign, in which I have many textboxes describing images. To these text boxes I applied a double border called "End End" to which I then applied the "Indented" Corners option.
The error occurs when I export the book in ebook format, the edges of the frames are often cut off to the right and below.
If, on the other hand, I export to other formats, such as PDF, JPG, etc., the edges of the frames do not present any problems.

What is happening?
I wasted a lot of time looking for a solution, doing various tests, but I couldn't solve it, is it maybe a bug?
I absolutely have to deliver the ebook, how do I fix it?
Thank you
