I am experiencing this in multiple projects, both between construction script/event graph and between blueprints using blueprints interfaces. Below are screen shots of it happening whilst using Digital Tutors project files. There are 15 blue pickup actors in the level, but it returns as 0
This could be an order of operations issue. The MyGame construction script is most likely being executed before the pickups are being created. In order to test this, try taking the logic that you have in the construction script and moving it to the Event Graph under Event Begin Play instead. This should allow you to get the correct number of pickups that you have in your level.