Thank you all for your replies,
they are very interesting.
The problem I had was probably due to the high temperatures we currently have (95°F) The glue adhered more than usual.
Used on the other side? It's worse.
It's not birch it's oukoumé plywood used for outdoor work, I don't like birch, I can't work it
I could paint it but...
sand it? why not but I'm afraid to break some parts.
I'm undecided, I'll going to leave it for some days
If I'm brave I'll do it again but not in the next few days.
Bonne journée à toutes et à tous.
Eric