Built-in keyboard not working after replacement

Hi,

I'll try to keep it simple: One and a half year ago some oil spilled overy my macbook. I cleaned it as much as I could but did not unmount the keyboard. One month later, the R key stopped working. Months later also the I key and U stopped working too or I had to push it very hard to make them work.

Following the procedure I found on this website, I replaced the keyboard and now all the keys do work properly but it is as if went on and off endlessl. I can say trhat because typing gets soo slow and if I go to

Settings > Keyboard I see on the bottom option blinking and going on and off repeatedly as you can see from the attached screenshots.

I assume it might be some connection hardware problems, I've tried several times to reconnect the keyboard but it keeps always doing so.

What can it be?

Please help it is so annoying!