Hello and welcome to Just Answer.
The flashing light is a message to tell you there was an internal error in the transmission. I suggest having the dealer look into the concern. There have been many complete transmission replacements that were necessary because the problem was not caught soon enough. In some cases there has been only the replacement of the torque converter. If the transmission does fail on you it will take out the radiator due to the debris that is pushed through the transmission cooler lines.I have seen anywhere from $5,500-$7,000 for the complete replacement at the dealer. Don't hesitate I would call the dealer and inform them this happened after your previous repairs and they will most likely try to get you in ASAP.