Glad I’m not the only one. It may be that the memory leak occurs with other blueprints, but we a single one that is particularly big and is know to have cyclic dependencies, which is particularly troublesome. If you just leave the editor window with that BP open, the memory allocation skyrockets and kneels my PC in a few minutes: it occurs 100% of the times, the pattern is the one described in the OP. We resolved by trying to only do small edits on that BP at a time and to remember to close the editor window as soon as possible, when not needed.