TYPO3 Core

I found the corresponding code in the Typo3 Source.

Location: TYPO3.CMS/typo3/sysext/core/Classes/TypoScript/Parser/TypoScriptParser.php

Typo3 6.2.25 at line 483
Typo3 CMS (GitHub, Commit d1ecab6) at line 506 (should be v8, isn't it?)

if (strpos($line, '*/') === 0) {

should be changed to

if ((strpos($line, '*/') === 0) || (strripos($line, '*/') !== false)) {

Otherwise, multiline-comments only work if the ending */ is the first string/character group in the line.
Furthermore, this leads to a complete inactivation of every following TS-code (Extensions Templates or other stuff), as the following TypoScript is treated as part of the comment.

This solution checks the presence at the start (as before) and optionally checks for existance of an multiline-comment-ending-string, beginning the search at the end of the string.
Please beware of using an explicit position for the strripos() comparison with this technique, as there may be whitespace characters at the end (in this case, rtrim() is needed).

If this solution is not accepted, the syntax highlighting should be changed, as the commented section is still treated as a comment in the backend template editor, though the comment-end is not detected by this technique. Still, this needs to be verified and checked by somebody for possible problems created. My tests didn't result in any problems.

Patch set 7 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/74987

Applied in changeset 09c61884bf2f15b0f209f8b177268620fc77cc8a.