it is possible to connect two incompatible types to an Array Blueprint function node by connecting the Item pin first.
The type of Array function nodes is determined by the first thing connected to them and it is therefore possible to create an Array function of type Object, and connect the actual Array to it second, and the editor will let you do it since an Actor is an Object. It should detect on compile that this is not valid but it does not.
Result: Blueprint successfully Compiles.
Expected: Error Object types are not compatible.
Note: Upon resetting the project, the blueprint properly displays the compile error.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-74885 in the post.