Both exist in POT file and in Phrase system. I don't see why it's not translated.
On my test system:
I think the PO/MO system has own cache or so.Try to change WordPress language to English then back to Hebrew.
Also maybe you've added these phrases twice in wpForo Phrase system. I recommend navigate to Dashboard > Forums > Phrases admin page, search these phrases and set values empty. then delete all cache, and check it again.