do you have a single /focus line or multiple ones? Blizzard recently changed focus so that if the person you are focusing is not near you, it CLEARS the focus instead of leaving it alone. ie this won't work:

/focus charA
/focus charB
/focus charC

if A is online and B and C are not, it will clear focus every time you run it. The macro I use instead is:

/clearfocus
/cleartarget
/targetexact charA
/targetexact charB
/targetexact charC
/focus
/cleartarget

works fine with jamba for me.