TYPO3 Core

The search for docs in sysext:documentation shows a weird, unexpected behaviour in TYPO3 CMS 6.2 LTS beta4

Fresh, clean TYPO3 CMS 6.2 LTS beta4 installation.
Go to Backend -> HELP -> Documentation
Switch from function "Show Documentation" to "Download Documentation" (dropdown box at the top)

Example 1: Security Guide
The "Security Guide" appears in the list (key: t3security)
Enter "security" -> No matching records found
Enter "sec" -> No matching records found
Enter "se" -> No matching records found

Example 2: something with "typo3"
Several docs with the keyword "TYPO3" appear in the list
Enter "typo3" -> No matching records found
Clear the search input field (complete list appears as expected)
Enter "typo3" and remove the "3" (backspace) -> result list looks ok

Back to example 1:
Enter "security" and remove the last character "y" (backspace) -> record appears correctly

Example 3: ext:rsaauth
The manual I am looking for is "RSA authentication for TYPO3" (ext:rsaauth)
Enter "rsa" -> No matching records found
Enter "rsa" plus a space at the end, remove the space (backspace) -> looks ok
Clear the search input field
Enter "rsa" -> now it looks ok (was not before, see above)
Clear "page content cache" (flash-icon at the top)
Enter "rsa" again -> No matching records found

Example 4: RTE
Enter "rte" -> two docs appear in list: t3api and t3tsref
Remove the last character "e" from "rte" -> two different docs appear: rtehtmlarea and t3start
Add the "e" again -> No matching records found