What it requires. Apex actions, invocable actions, email actions, and subflow calls must not appear inside a Loop element. This extends the ban on queries and DML in loops to every element that consumes per-invocation limits.
Why it matters. Flow bulkification batches executions of the same element across interviews, but an action inside a loop still executes once per iteration within each interview, multiplying Apex, email, and callout limit consumption exactly as DML in a loop does. A loop of 200 iterations calling an Apex action makes 200 invocations in one transaction.
How to fix it. Collect the required inputs into a collection inside the loop, then invoke the action or subflow once after the loop with the whole collection, or redesign the action to accept collections.
Is this rule worth checking?
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