I would have liked to to have seen a tapered sill with some flex tape tied into the exisiting weather barrier followed up with an aluminum sill before the window was set at the time of installation. At this point it will be difficult to do . The reality is these type of installs can look great and professional when completed but the truth gets burried behind aluminum work and caulking . Problems like this have a tendacy to show up years later. installing windows is often all about contolling the flow. I think they messedup and i have my doubts they will correct this properly.

That doesn't look right at all. You need more than mortar.

The jamb depth of the new window doesn't match the jamb depth of the window removed, which the contractor should have accounted for before he ordered the new windows. Now they will have to add some type of exterior trim around the windows, mortar or caulk alone won't suffice.

They could have also put in there own jamb extensions to bring the window out . At this point water control is probaly going to depend upon a caulk joint which is undesirable .

Im pretty certain this was not done by a window contractor. Its abundantly clear that this was performed by a low priced handy man with an unusual sense of humor.

This is a great example of you getting exactly what you paid for.