Has anyone replaced their brake actuator only to get P0a78-526 and other connector codes?

No, just the top cover. Each time taking careful consideration to all of the plugs inside of it.

 

Right, I'm taking your advice and will re check all of the connections. The only other thing that might have happened, is when I first changed the brake actuator, and tried to add and bleed the inverter fluid, I discovered that the pump was not working. So I changed the inverter cooling pump while changing the brake actuator the 2nd time. Then added and bled the inverter fluid. My thinking is the car ran with it hot, but didn't throw a code due to it being driven like 5 miles in NYC (Brooklyn) where my daughter lives. SO when the fluid recirculated, possibly a crack in the inverter somewhere caused the red triangle, or maybe I watch too many videos....

 

Well, I installed the brake actuator, and newly purchased inverter, went into techstream and did the brake bleed, linear valve reset, zero and cleared the codes. After starting it and backing it up, I got the red triangle and c1364.
Next day, went back out, cleared the codes, checked everything again, and was able to drive it around the block. No codes, no lights, no red triange. I must admit, I'm going to test drive it tomorrow for a good 1/2 hour or so, then see if I can consider this case closed.

 

C1364 comes up each time I start the Prius. I can delete the code with my scan tool, and drive it without any issues. Then, stop to get a coffee, turn it off, restart and c1364 appears again. Scan tool delete, off to the inspection station to get new annual NYS inspection. Only 1 monitor was ahowing, so it passed with no issues. Looks like another bad brake actuator, so off to ebay I go.....