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This is very weird. It's happening again now but it was fine earlier today a few hours ago.
The first picture is one of the cards I was studying on Ankiweb, for which I clicked "Good" (<10m). However, the card did not go into the learning deck. When I searched the card via the computer version, the card info says interval (10m), but due date is tomorrow.
Finally, that's just another card that had the same issue. But, as you can see, earlier today (@12:48), the 10min interval worked. The card was put into the learning deck and I was shown the card again when I logged on. However, after the second time I chose the 10min interval (@18:26), the due date jumped to tomorrow (6/14).
When I woke up this morning and it was working, I thought it was just a glitch last night. However, now I'm very puzzled as it seems like it may be dependent on the time of the day? I will see if the same thing happens tomorrow :P
Did you disable and enable the V2 scheduler, or has it been on the whole time? If you turned it off, it will remove any cards from learning. Do you have any add-ons installed on the computer version? If you limit your study to the computer version (to rule out AnkiWeb as a factor), do you find the issues remain?
V2 scheduler was on the whole time during this. I don't think I have any add-ons installed. The computer version works fine. It is only on AnkiWeb that this is an issue.
I am aware that V2 scheduler resets all cards in learning, but these are new cards that I tried to study after turning on V2.
I did try turning V2 scheduler on and off yesterday to see if this problem would resolve. When V2 is off, AnkiWeb works fine and there is no issue. This only happens when V2 is turned on and I try to schedule the card to be shown again on the same day. Also, I noticed that when I turned V2 off after it started doing this, the due dates for these incorrectly marked cards becomes some date in 8/2018, which I also could not understand.
I haven't been able to pinpoint the exact time, but from what I've been observing, the problem starts occurring sometime in the afternoon, as early as around 3pm and last throughout the evening. It resets at 12am when it is the next day and the problem is gone, but comes back the next afternoon.
Also, another interesting thing I've found is that when the problem is there, Ankiweb refreshes after every card rather than refreshing after every 5 or so cards when it is working normally.
Would you mind giving the following change a go to see if it addresses your AnkiWeb issues? You'll either need to wait until the next stable release of the computer version and AnkiMobile, or install the betas of each.