Yeah i hit a rough patch, made a similar post on the forums, people told me to keep on learning new ones, so i did and the ones i had troubles with kinda faded! .
It's better to learn 50 new ones, than be stuck on a few.

Some stuff is harder to learn than others.  There are definitely some kanji that I have a -very- hard time with, and others that are very very easy.  Sometimes they clump into patches...  If you got an 'easy' patch, then a 'hard' one, it is going to be frustrating like this.

Keep going.  Don't let it get you down.  Once you get to easy ones again, you'll get your momentum back and it'll all be good.

I feel the same way about reviews sometimes. But then I remind myself that forgetting and remembering a kanji is part of learning it, especially in the short term. After I remember it, I find it sticks a little better the next time 'round.

If a character doesn't stick multiple times, that's an indication to me that I need to retool the story.

Also, it might help to review the pointers Heisig provides on page 97 of RTK (well, page 97 of the 5th edition anyways; it's the opening text of chapter 11). I skimmed over it the first time through, but after going back and re-reading it, I've found that his advice there helped me a great deal with remembering characters.

Whew, I've pressed on and I'm glad I did! I'm having fun with these weather kanji. I seem to like things like that for some reason.

I'm in the late 300s as well. definitely hitting a rough patch with these not sticking, but like everyone says, just keep on adding cards!

i also have a tough time with element-construction. i tool my stories typically so the elements read left-right, top-bottom, which solves issues of which of two kanji go on the left (many of heisig's stories reverse the natural written order of appearance).

however, it's tricky when sometimes there are two kanji above, one below, or one above, two below, or two on the left one above the other, and one on the right. often i'll remember a story, and even the elements, but neither one helps me remember the organization of the elements. that can get frustrating sometimes.

It is something that takes care of itself in the long run. Remembering the primitives seems far more important.

Nukemarine once posted that he only started to be strict about the positioning of the primitives in his reviews after the completion of RTK. I did the same.

What you can't do is think everything is gonna end when you add the last kanji in the SRS.