This episode is mainly focused on providing a back story for Kagari and on a first viewing is entertaining enough. We know something about Karagri but this episode sets up the mystery that Okabe has to now solve.
There are two minor issues with this episode, one it the character of Karagri is new, thus most viewers have made no investment in her character. She looks like Kurisu, but she is clearly not Kurisu and Okeba makes that clear. When we are dealing with an uninvested character the writers need to add an addition pull to keep you glued to your seat. In the 1st series it was the antics of Okabe and the conflict with Kurisu, which in itself is entertaining. The last episode where we fleshed out the backstory of Maho we had the antics of Faris, especially with Moeka. While this is cheap, its amusing and entertaining, thus the writer has left sweets along the trail which will lead to their investment in a character. This episode lacks that.
On a first viewing you are invested because you want to know the answer to the mystery, on a second viewing its all filler which can easily be skipped. Only a minor issue, but the 2nd season is not as tightly written as the first and it can show sometimes.