Captions under larger image aren't fitting under the image

Hi, We have a problem with some images with captions. I have changed the background color of the captions and have made the text left-aligned instead of centered. The problem is that with the caption styled for 100% width it is extending far beyond the left & right edges of the image. It would probably be fine if the caption were wrapping the image, but the current too-wide box looks quite odd. Small ones with short captions are ok. So far I only have one example of this which is in draft form only so I am sharing a screenshot. too much caption! I tried changing the percentage but the problem I see with this is that while it might fix this image this approach might cause yet more problems with others. The ideal solution to this would be (if the captions continue to be on the bottom) for the caption to be responsive with the image, never being wider than the image. I found this post and tried it without the suggested fix, and it didn't seem to make any difference. Make wp-caption the same (responsive) width as the Image Can you offer a solution to this? Thank you