TYPO3 Core

OK, first part of the puzzle: The captions are passed as newline separated value inside the data:imagecaption = \nCaption Image 2\ncaption image 3

Thus the first caption is empty ... I guess later this empty value cause the other to shift ... I will now go in with debugging ;)

Ha ... and next comes a trim :D This removes the \n at the beginning ... in PHP trim(content). This leaves us with Caption Image 2\ncaption image 3, which means now caption 2 is shifted to caption 1 ;)

You can help yourself by removing the trim = 1 from stdWrap.

tt_content.image.20.caption.1.1.trim >

That means also that you must not have any newlines in your caption.

I think this could be an heritage of version 4.7: if I remember, prior to FAL, the caption field was a single field against multiple images, and you had to separate the captions with a new line: a line for each caption ;)

Patch set 2 for branch master has been pushed to the review server.
It is available at https://review.typo3.org/20884

Patch set 1 for branch TYPO3_6-1 has been pushed to the review server.
It is available at https://review.typo3.org/21726

Patch set 1 for branch TYPO3_6-0 has been pushed to the review server.
It is available at https://review.typo3.org/21727

Just for the record: this also affects TYPO3 CMS 4.7 and is a regression introduced with 57102904d645540a74d0519cfb8ebcc28fc20820