Use location and timing to separate plumbing, drain and waterproofing pathways around showers, drains, seals, extract ventilation and wet-room layers.
What the timing tells you
The phrase after showering is diagnostic context. Compare the symptom before, during and after that trigger.
What is special about this location
Showers, drains, seals, extract ventilation and wet-room layers create pathways that are not visible from the finished room.
Start with competing explanations
Compare plumbing, drain and waterproofing pathways. Do not select a cause from appearance alone.
First useful check
Use the linked check to create a timeline or pattern, then follow the strongest cause family to its full dossier.
Repair decision
Avoid cosmetic work until the source or mechanism is controlled and the original trigger no longer reproduces the symptom.