Check Auto-Drying and make sure a mop wash or mopping run actually triggered it.
Roborock says Q Revo auto-drying must be enabled in the app and normally starts after mopping or mop washing. If drying starts but the pads stay damp, leave the robot docked and increase the drying duration in humid conditions before assuming the dock fan or heater has failed.

Find why the mop pads are not drying
Is Auto-Drying enabled in Dock Settings?
This is Roborock's first official check when auto-drying does not start.
How to restore Q Revo mop drying
Enable Auto-Drying
Open the Roborock app, go to Dock Settings and confirm Auto-Drying is switched on.
Trigger the right dock sequence
Drying normally follows mopping or mop washing. If you are testing after a vacuum-only run, start mop washing first or use the app's Drying control.
Leave the robot docked
Do not move the robot away from the dock during drying. An interrupted cycle can leave the pads noticeably damp.
Increase drying duration in humid conditions
Roborock recommends a longer drying duration when ambient humidity is high. Change the duration in Dock Settings and compare the pads after a complete cycle.
Power-cycle once if manual drying will not start
Disconnect dock power for about two minutes, reconnect it, then retry a manual drying cycle from the app.
When to stop DIY
Q Revo uses a built-in warm-air drying module. If a manual drying cycle produces no drying effect after settings and dock position are confirmed, do not open the powered dock to reach the fan, heater or internal wiring. Use qualified service.
Use a different guide if the symptom starts earlier
Mop Pads Not Getting Wet
Use this if the pads stay dry during cleaning instead of staying wet after the robot returns to the dock.
Dock Not Washing Mops
Use this if the dock does not complete the mop-washing step that normally comes before drying.