Just a suggestion.
I often have the problem that i can’t make any changes to my raid- or invasionteams, when i’m out of sigils. My suggestion is this:
add a teamslot to the list of normal teams that shows the eventteam. When selected ist just the same screen it shows if one goes throu the path guild->raidboss/invasion->fight->edit team. While there is the week of guild wars the team just is empty.