Hello Thierry,
there appears to be a bug with beans_replace_attribute() when specifying an empty value for the "new_value" parameter (which should replace ALL values with the provided value).
This was working fine in version 1.4 and that breaks website when upgrading to version 1.5.x
Thanks.
I submitted a PR on github for this which resolves the issue. This is a breaking change, please look into this.