Three detection checks run every time a Managed Software Delivery policy is executed.
The product is working as designed. The first detection check determines if the policy should proceed to download the package. The second detection check determines if the policy should proceed to install the software in case the software gets installed through other means before the package download finishes. The third detection check confirms that the software was installed.
If the software is detected the three detection checks will still run but there will be no package download or software installation.
There are no plans at the moment to change this.