when logging in, there is a very long delay - and instead of waiting for the home page it is faster to close the tab and reload memrise.com in another. IOW: the login works (cookie is set) but then the next action seems to be an endless loop.
This also might be paired with the general lag in general with the site for certain areas (which has been going on for sometime.) Going from section to section (forums, topics, gardens, home page) can be excruciating - most of the site has speed problems, but then there are a few areas that do not. This also affects learning - when getting words right, there is quite a long time until the next word appears. It doesn't seem that long in numbers (maybe 2 seconds) but it can be quite a detriment to learning quickly.. if I need to go through 500 words in 10 different gardens it might take an hour where it should be more of a 15 minute run. I prefer to do each garden separately to keep track of which words belong to which garden - also it sometimes happens that `water all' brings words in that are not in my gardens.
Perhaps the delay between correct answers is by design - then it would be nice to set it to instantly go to the next work if desired instead of waiting while the bouncing 5 in a row congratulates you.
more insight and investigation along with examples can come.. but it's going to take some time.