Seeing as your screenshots seem to all be taken from the moment of the breakpoint triggering on the last node, I’d say the variable value displayed on that last hover tooltip (where it says Cargo Capacity 0) is probably fake. The variable isn’t used for the node your breakpoint is on so there’s AFAIK no guarantee that it’ll remain properly cached, and I wouldn’t rely on the tooltip info as factual.
When in doubt just add some temporary Prints, they’ll always print the correct value.