There is no definitive root cause for CPD hours being recorded excessively.
One common reason is users leaving modules open or not exiting the module when they leave their device for an extended period, resulting in a much higher time showing in their CPD log than expected.
If this occurs, there are two ways to correct a user's CPD hours.
Manually amending a user's CPD time. Overwrite the time the user spent completing the module with the correct figure.
Apply CPD cap to users on a module. Limit the maximum CPD time awarded for a module.