I am having this same issue too.
I have 5 servers in a multi-server setup of ISPConfig 3.0.4.
On the main Monitor page, all 5 servers show GREEN with ticks, and:
State: ok (0 unknown, 0 info, 0 warning, 0 critical, 0 error)
However when I drill down into "Show Update State" of various servers, I get a BLUE box with "i" icon, showing updates need to be done.
Previously the correct statuses would be shown on the main page, not ALL green.
Now I can't see if various servers need updates, or have disk getting full, from the main page. I have to drill down into each server.