I got again a SSH crash with 5.0 RC1 on RB750G.
This seems to produce randomly, after a few hours to a few days of uptime.
I'm using dude to probe the SSH service on this router.
I'm not alone to have this problem. From another thread in the forum :
"Confirm STILL bug in Beta 6 on RB-450G
got scared when I couldn't log into remote site... luckily I have a tunnel that accepted a telnet session. <whew>..."