Have text lines in a contents like this, where the space is a tab:
DENTITION 287
INDEX 299

The paragraph style uses these two GREP style lines to apply a character style that changes the point size of the number to 8.5 pt.
\t[ivxclm0123456789]+[\r\n]+
\t[ivxclm0123456789]+\z

When the text line is at the end of a frame the number is formatted correctly per the character style at 8.5pt, but when the number is selected InDesign shows the wrong size in the menus, unlike the other numbers NOT at the end of the frame, which shows the point size the number actually is (8.5pt).

Also, the number in the line at the end of the frame does NOT get mapped to the XML element to which the character style is mapped, the other numbers DO get mapped.

When creating a PDF, the point size comes out correct as well.