When I make a long tap on the portal on the map, and click "hack with key", the hack happens, but the key does not drop out, if it is already in the inventory.
Why do you think that the game must give it to you?
Because the same button from the portal menu works correctly and additional keys drop out. What's the point of this button if it doesn't give a key?
I just did it today and it gave a key. Just like glyph hacking with More (request key) doesn’t always give a key, neither does the Request Key quick-button. It’s a request, not a promise or demand. From what I’ve experienced the quick-button fails more often than it succeeds. But it still works. If you need keys, glyph hack and apply the More glyph.
The same button from the portal menu works in the same way, it give you just a chance of key after hack. Now at 2.61.3 i tried long tap hack with key on my device and got my key while already had 3 keys from the portal in inventory. The next time i won't get lucky. It's absolutely normal way how the game works. If you can't get key from any portal after many attempts, maybe it's a bug, but please provide to us information about your device and version of the game. Because the bug if it exist, doesn't affect to all players.
Yes, the same button from the portal menu gives an additional key. The button from the map never gives you a key if you already have one. This is a common hack. If the logic of the game is like this, then the picture on the button should be different.
Logic of the game is chance to get a key after "hack with key" even if you already have key in inventory. If you do simple hack when already have the key in inventory, you don't have that chance.
Surprisingly, it now works correctly. The issue is resolved. Thanks.
It was never broken.
Each hack 'with key' only has a 75% to drop a key. Every 'chance' at a key, even the extra chances granted through Glyph Hack bonus, each have only a 75% chance of success, which is why you see different numbers of keys, and can get a P8 perfect hack with 50+% speed bonus, and still get no keys.