Middle managers routinely carry tasks that appear on no job description and in no quarterly plan. The reason is structural rather than personal: they occupy the seam between systems designed separately.
Organisations are built by function and work moves sideways
Companies are staffed by function because functions are easy to budget and easy to hire for. The work itself, though, moves across those boundaries rather than down them.
Every handoff between two functions creates a space where responsibility is defined on both sides but not in the middle. That space belongs to nobody by design.
Managers on either side are the first to see when something falls into the gap, and in most companies noticing a problem is treated as owning it.
Escalation travels upward before it travels sideways
When a problem crosses a boundary, the fastest available route runs up one reporting chain and back down another. That path passes through managers rather than around them.
Each escalation arrives framed as a request for a decision, but most arrive missing the context that only the originating team holds. The manager rebuilds it.
That reconstruction never appears in a ticket, a plan or a performance review, yet it can consume a substantial share of a manager's working week.
Absorbing the task is cheaper than renegotiating scope
Pushing an unowned task back requires a conversation between two functions about where a boundary actually sits. Those conversations are slow and often need a more senior sponsor.
Doing the task takes an afternoon. The manager compares an afternoon against a fortnight of negotiation and picks the afternoon, which is locally rational every single time.
Repeated across a year, those afternoons harden into an informal role that nobody wrote down and that disappears entirely when the manager changes jobs.
The absorbed work is invisible to the systems that measure output
Planning tools track work that was assigned. Absorbed work was never assigned, so it sits outside the plan and outside any estimate of how much capacity a team has.
This makes managers look underloaded on paper while running at full stretch in practice. Additional projects get allocated on the strength of the paper picture.
It also means the cost of a badly drawn boundary never appears anywhere it might be noticed. The organisation pays for it in manager time instead.
Making the seam visible is the only durable fix
Naming the recurring handoffs and writing down who owns each one converts invisible absorption into an explicit assignment that can be staffed, measured or removed.
The exercise usually reveals that a handful of seams generate most of the unassigned work. Fixing those few is far cheaper than adding managers.
Where a seam genuinely needs a person, giving that person the role openly beats letting a manager do it by default and calling it initiative.