transmission (copy/move) queue broken

When using the transmission queue by setting simultaneous transmissions to "local files only on the same devices", then starting 3 separate copy jobs, #2 and #3 are initially delayed, so far so good, but after #1 finishes, #2 and #3 start simultaneously copying even though they share a source / destination HDD. In fact, when #1 finishes, all other jobs that waited for #1 are started.