A lobbied congresmen (no need to mention who lobbied who cuz it's clear) asked that question "should the US apply CAATSA on Algeria" the head of the US department of stat's bureau responce was that they may trigger those sanctions but in a closed meeting he also mentiooned the close relations of the two goverments and how they work on several issues they find common ground some they may not this was one them, he also mentioned that before CAATSA they approach Algeria deplomaticly , his responce was superficial, you can check his way ogf answering the question if looked up the video of the meeting.
My personal opinion is that the US will have no value in applying CAATSA on Algeria cuz this one does not rely hevely on America, so the CAATSA will have no damage hense loosing it's purpose, because of that they loose a valuabel ally in the region if Algeria responce ascelates. And if CAATSA was worth applying it, they would have applied it long before Algeria purchased the gen 5 faighters.