Strange "bug" in dump ?

Dear all,

When doing a dump of a 8.1.17, database (that I have to reimport daily
into a 7.4.6), I have a strange bugs with accents...

First point, I had to add --insert.

But there is still a problem with accents.

If I say nothing the dump is utf8, or I can add -E=latin1.

But in both cases it fails, and there is a very strange error !
There is a "E" before the street field !

This is an extract of the dump :

'ST311PHANIE ROBERT', NULL, E'RTE DES TATTES D\\''OIE 5',

311 is shown instead of accent

Does someone knows what could be this problem ?

Denis