The error is the same as basic disconnection, it must be the game since you're not the only one experiencing it (me & other people have the same issue), I suggest to either wait or try to play slower.
I have the same exact problem as Levia, but only in Zone 6.
This seems to only be affecting Wolfdog characters.
...I don't know about Harpy, but the disconnections stopped occurring when I stopped using FM1.
It's happening to me, too, from time to time. It's most definitely something wrong with the game, not you.
As frustrating as it is, do try to be patient until they fix it :/
It's been happening to me too with Levia. It seems to happen whenever I hit too many enemies at once, and only seems to happen in the last two Area 6 stages.
With Levia at least, it seems to be linked to any skills that involve her "snakes". (Horn Gouge's Advanced command, Fang Dive, Designated Flight.) And for 6-7, it's only happened on the first segment (the elevator) so far.
Edit: Never mind, it just happened when I used Black Sabbath in the second area of 6-2. (Wiped out all the enemies but the miniboss.)
However, Black Sabbath still involves "snake" animations. It seems to me whenever I hit too many enemies with "snakes", I get disconnected.
Edit 2: Never mind, as soon as I logged back on and used Judgement Star in the same spot instead, I still got disconnected.
So maybe it's not "snakes" and it's just scoring too many enemies at once while standing on that elevator platform. The elevator platform seems to be the common theme here.
But then again, it happened in 6-6 once after using Fang Dive.
Someone said it happens when you reach a skill chain Lv20 or 200hit? I forgot, but it should be related to one of those 2's amount..
200 hits in a short amount of time, maybe.
I've been running 6-7 VH with Seulbi and gotten a few 200+ combos, but since her multihit attacks are slower compared to everyone else's, she hasn't gotten disconnected.