I’ve been looking for a silver bullet that will make this “resourcing” strategy somehow less terrible for trying to be agile but… there isn’t one. Whichever way you slice it, making people less than 100% on the team creates dysfunction.
It makes scheduling team collaboration opportunities difficult. It also means that people on more than one team spend more of their time with agile meetings than they should (think two or three lots of sprint reviews, planning meetings, retros…) - or they skip meetings because they have to. Perhaps most insidiously, it means that people are probably 100% ‘utilised’, at least. We know what happens to lead time as untilisation approaches 100%, right? It increases exponentially. So, basically, it’s a nightmare.