I've seen this a lot in various forms. It's likely related to the engine. So many support issues I've seen with the 5EAT have been resolved with something as simple as an engine vacuum leak. I do not know what the exact mechanism is, but it's the ECU sending incorrect signals to the TCU. ECU itself is fine, problem is an input somewhere is not what the TCU wants to see at certain moments, such as during your bad shift.
The solenoids are easy to change, just one torx bolt and gently pulling it out (plastic held secure by two o-rings). They are now also easy to find, and not terribly expensive. Just make sure you don't buy one of questionable origin, as with any aftermarket replacement part.
What was your CEL Code? Not P0700, but the next code, something like P0741. Let's first double check that you replaced the correct solenoid... PM me too about this, happy to help.
For a time I really came to dread dealing with my LGT and all things related, but I'm in a better place now and I am starting to enjoy it again. Might be on here a bit more often