I followed the proposed process. I remove and delete members with no effect on the «in progress» sprint or even planned sprints. So when I click on «Project team» a get a list of people and when I click on «availabilitiy» for the «in progress» sprint I get another different list of people.
We use Icescrum on our own server.
Our version: R6#14.10 Pro Standalone
Thanks for your help.