This at least applies to captions on images when the caption is below the image, which is the typical scenario for caption. It is not relevant for table captions, since with tables, the caption is just created as a separate paragraph in the normal document text flow.
Steps to Reproduce:
1. Insert an image into a Writer document
2. With the image selected insert a caption
3. Change the Caption paragraph style to use Small Caps font effect
The caption's category label (Figure, etc.) disappears.
The full caption should be visible.
User Profile Reset: No
This also happens if you select everything inside the caption frame and apply Small Caps as direct formatting, or if you select the caption plus a mysterious invisible something on the line above (the line that the image is on) and apply Small Caps.
The label is not hiding behind the image. If you make the image transparent you will see that the label is in fact gone. Yet, if you delete the image, the label reappears!
Workaround: set the image anchor to Paragraph.
Alternate Workaround: click on the caption text, move the cursor all the way to the beginning of the text frame, before the image, then press the right arrow key once so the cursor is now on the right side of the image, then press enter to create a paragraph break between the image and the caption.
Obviously this won't effect a lot of people and the workaround is OK *if* you know to do it. But it is strange and I think it is just another example showing that captions are handle poorly in LO.
And what is that mysterious invisible thing between the image and the caption? It doesn't show up when you display formatting marks, and it doesn't even exist in the text flow, based on moving the cursor with the arrow keys, and yet there is clearly something there.
May or may not be related to https://bugs.documentfoundation.org/show_bug.cgi?id=97397, but they should be dealt with at the same time, imho.
Third workaround, select the image+caption, or at least the mysterious invisible thing+caption and then Clear Direct Formatting.
Confirm with Version: 126.96.36.199.alpha0+
Build ID: 65438bcda46bab4f2fe6fb555f44aace45e11e5e
CPU threads: 4; OS: Windows 6.1; UI render: default; VCL: win;
works correctly in Version 188.8.131.52 (Build ID: 7545bee9c2a0782548772a21bc84a9dcc583b89)
I confirmed it with:
Build ID: 98c6a8a1c6c7b144ce3cc729e34964b47ce25d62
CPU threads: 4; OS: Mac OS X 10.12.5; UI render: default; VCL: osx;
Locale: en-US (ja_JP.UTF-8); UI-Language: en-US