The in progress crafting item eats up all the high-quality lenses, it shows that 5 high-quality lenses are in use (went up to even 10), but when I try to craft the item, it says the high-quality lens is missing and when it prompts me to ask whether to craft it, that’s the moment when it eats more lenses. Build 9271.
EDIT: So, the components required for the telescopic sights for both the pistol and rifle telescopic sight mods show at the time (both recipes are identical):
2 high-quality lenses of 2
1 small high-quality lens OR 1 high-quality lens of 2
When I try to craft these mods, it eats up 3 lenses initially.