Hi, after a lot of test i discover the problem.
Using anykind of gutenberg block plug in then using th block called: conteiner, sections and so on (particolar blocks that have to change colour back ground ora move posizion and so on), when insert Classic editor after save the page the next time that open the page always the block editor fault and have an issue.
I tested with this block plug in : Ultimate addon block (Scection block)
and plug in: Stackable (Conteiner block) same error
Someone have any idea why this error?
thanks