Storing a performance should be instant. Please start your Profiler into browse mode while keeping the RIG button pressed until you see "Checking content" in the display. This will force a rebuild of the internal database and potentially will fix your issue.
After a Rig reset, I still experience latency when RM is connected: when I press the Store button nothing happens for 1"-2", then the Store button starts to blink, then the sync'ing graphic appears on the display, then the operation is over. I'd say 3"-5" overall.
Timing seems unrelated to the complexity of the editing.
Everything updated to latest KAOS 8, Lunchbox with Remote and an exp pedal connected, W10