Twitch bothced their drop system entirely and where you previously could rely on having the drop automatically transferred to your account, nowadays (and for a number of months) you have to "claim" drops either through actively viewing the content and then clicking a popup button, or going to your Twitch inventory and press a "claim" button in it. A drop will only be eligible to claim for a set amount of time, if I recall it right it's 7 days from after the drop was earned.
That's the explanation I can think of, that you haven't pressed their stupid "claim" buttons for these drops.