Unsure if this is intentional or not, so posting under Bugs.
If your fleet arrives at an enemy planet on the same turn as a Weapons upgrade is completed, the battle will still use the old Weapons Tech Level.
Similarly, If you unlock Banking on the same turn as a new Cycle, you will still only get the old Banking value for that cycle.
The reason I’m posting under Bugs is because in the Event log, things are presumably ordered from New to Old, and the Research upgrades always occur before the Battle or before the Cycle messages. That makes me think that the new Tech values should be used in all subsequent events, but they are not.
Either this is intentional and the messages should probably be re-ordered, or the Tech values should be applied before any subsequent events even if they’re on the same turn. (IMHO)