Actually, I take it back, I did the 1 connection wrong.. Doing the
connection directly didn't trigger the problem.
Thanks Luis, your suggestion made me close the scope in the issue! It was
actually a cache done by default by Ecto (Elixir's database library), I
just created an issue in Ecto's github
https://github.com/elixir-ecto/ecto/issues/3284 and got the response
confirming it and also the fix to disable it.
Thanks you all very much for the help!