Perhaps the cursor is actually in the correct place but is just getting displayed in the wrong place. I have experienced this with right-to-left scripts on some systems. To test this:
- In a new document, type one word, press space, then type another word.
- Save as PDF.
Are the words rendered correctly in the PDF file?
You may find that the stable version has more reliable rendering than the "fresh" 5.x series. I have had trouble with several scripts when using 5.x, probably because it has not been tested well enough yet.
Also try using a different font. Be sure to use a Unicode font such as Ezra SIL so that the word processor can interpret the symbols correctly.
Apparently some people have had success with Hebrew and LibreOffice on OS X. Search for "LibreOffice" on https://www.quora.com/How-can-I-write-a-document-right-to-left-e-g-in-Hebrew-on-a-Mac.