So I noticed from the item definition you listed above that you have one of your Rollershutter item not inverted while the other is. So I assume you are referring to persiana5 as being inverted. You can set the inverted=false metadata parameter since Rollershutter items are now inverted by default.
Rollershutter persiana5 "Persiana Cinco" <persiana> { alexa="Blind" [inverted=false], channel="mqtt:topic:mosquitto:persianes:P5" }
Rollershutter persiana6 "Persiana Seis" <persiana> { alexa="Blind", channel="mqtt:topic:mosquitto:persianes:P6" }