iPad Pro 12.9 blinking battery icon

My out of warranty 12.9 iPad Pro started showing the dead battery symbol and blinked on and off every 5 seconds or so. Of course I tried multiple cords and chargers but nothing worked. I Google'd and found several support posts with no real answers. I took to an authorized Apple dealer for support (i.e. Geek Squad at Best Buy) and they tried plugging in and told me they couldn't do anything to repair it. I called another repair shop that replaces iPad batteries and they quoted me around $400 for repairs. I just put it in a box and forgot about it for a few months. Today I was watching YouTube videos and found one that told me using a hair dryer to heat up the case to "jump start" the battery sometimes works so I tried that to no avail. But then I found another video and they had the answer, and it worked! It was so simple, but yet so perplexing.

For two years I have used a variety of cords, chargers, and plugged directly into my iMac and had no problem, so when this happened I never even thought to use the original power brick and cord it came with. I dug through piles of old cords and bricks (I have like 5 iPads of various generations) and managed to find the original brick and cord. I plugged it in and low and behold, 5 minutes later it came on and had 12% battery.

The person in the YouTube video guessed that Apple might have made a change in an update that required the original brick and cord probably due to different power amps/watts for the larger iPads that just charged it "slower" with smaller or 3rd party bricks in the past but now requires the original (or at least one that has the identical power specifications needed).

Hope this helps anyone who may be having the same issue.