Longbow Base Tip Mission Lag

Pretty much everything since GR/i18 has ran perfect for me except tip missions in Longbow bases.

The lag and huge drop in frame rate make these missions almost unplayable. I've gotten in the habit of just auto-completing these tips as I get them. I forgot the command to see your frame rate in-game, but I'd estimate my frame rate drops to 1-5 fps.

Anyone else experiencing a similar problem in these maps only?

Longbow base maps were always laggy for me. I guess, it is somehow related to textures used on these maps, because similar crey lab maps are much better lagwise.