Well since I had some more blueprints and such things around I tried using them all, thinking that using 3 or just more than 1 at once would work.

So going to ruby ring schemes choosing use and inserting 3 as the quantity I thought it will just take the 3, but it didn't.

It was only using 1 at a time, not giving any boni and not using more than 1, so to use 3 I had to go back and use 1 and 1 and 1 till I was done.

I just thought since we can use more it should allow us to use more, besides it wasn't giving of any warnings or error messages either which would make one think that you may not use more than 1.

I noticed this "bug" too while upgrading my schematics -- though this was pretty much expected behavior by me because I've coded game websites before.

This isn't really a bug so much as it is a limitation of the coding. They could probably make it use multiple schematics/blueprints by making it iterate over loop for the code it uses to update the schematics -- but then you'd need to error-catch trying to use more than one at every step of the loop (because the limitation that you can only do this 5 times per scheme/blueprint is there) so if the total of current plus the total of proposed (e.g. the quantity you put in the field) uses exceeded 5 it'd either have to give you an error stating you can't use that many (which would probably result in bugreports about a non-existant problem) or it'd have to use UP TO 5 and then kick out the rest and give you a message about how it used x and you still have y.

Either way, a big pain in the butt for a feature that will hardly benefit the site, and one little wrong line of code would mean someone loses some items and whines about how using multiple blueprints is bugged and they want their items back.

Which is why this will likely just stay a "you can only use 1 blueprint at a time" thing even though you can put in any number greater than 0 that you want. It still uses 1, you only lose the 1 you used out of your inventory (and not any extra), your blueprint still gets upgraded. Working as intended.

It's not a bug actually, blueprints are single-use item. We updated them to multi-use, maybe it's really more convenient. Now you can use up to 6 of the Blueprints at the same time if you don't have this recipe, otherwise the missing number of blueprints will be added to the maximum upgrade. There's no message about how many blueprints were used exactly but the unused ones will stay at your inventory if they are over the limit.